Click here for a "live cam" view of Mount St. Helens
CATANIA, Sicily (AP) - Experts were monitoring Mount Etna for a possible eruption Tuesday, a day after the volcano gushed lava and spewed smoke. Experts said the renewed activity did not present any immediate risk, but they were ready to evacuate residents in nearby towns if necessary. On Monday, thick streams of lava oozed down the deserted western side of the volcano, about 20 miles north of Catania. Mount Etna roars back to life every few months, attracting curious tourists. The last major eruption was in 1992.
LEGAZPI, Philippines (AP) - A Philippine volcano spewed thick, ash-laden smoke and burning rocks high into the air on Wednesday, forcing the evacuation of at least 2,000 villagers, officials said. Mayon Volcano, one of the Philippines' most active, shot smoke up to 3.7 miles into the air, but there were no signs that a major eruption would occur, the Philippine Institute of Volcanology and Seismology said. Disaster officials said there were no immediate reports of deaths or injuries.
The volcano is in Albay province, 210 miles southeast of Manila. Residents in Albay's capital city of Legazpi said they felt the ground shake mildly as the volcano spewed ash and smoke shortly before noon, sending many residents running out into streets. ``There was a loud booming sound, then a cloud of ash billowed like a cauliflower,'' said Ed Laguerta, head of the seismology institute in Albay. The ash and steam ejection lasted for about four minutes, then the ash column slowly drifted down on villages on the eastern slope of the 8,125-foot volcano.
Albay Governor Al Francis Bichara said the volcano also shot out burning rocks that ignited brush fires along a gully on Mayon's eastern slope, far from villages. He said at least 2,000 people were being evacuated to school shelters from three villages on the slope of or near the volcano. He said the villagers could return once the volcano stabilizes. ``Mayon has become so unpredictable and we can never tell when it's going to erupt. It could go off in the middle of the night,'' Bichara said. Residents near the volcano have been taught to wear gas masks or cover their faces with wet towels or shirts during ash ejections to avoid pulmonary problems, Laguerta said. Mayon, a popular tourist attraction, last erupted in February 1993, killing at least 70 people.
Scientists have been closely monitoring the volcano since it released ash-laden steam on June 22. Officials have advised about 1,800 families living in six villages within about 3.5 miles of the summit to voluntarily leave for safer areas, but many ignore such warnings. The danger zone was demarcated after the 1993 eruption. Mayon's most violent eruption was recorded on Feb. 1, 1814. The eruption killed more than 1,200 people and buried an entire town in volcanic mud flows. The Philippines is in the Pacific ``Ring of Fire,'' where there are frequent earthquakes and volcanic activity.
MANAGUA, Nicaragua (AP) - President Arnoldo Aleman on Sunday visited northwestern Nicaragua where at least 17 homes were destroyed by earthquakes last week following the eruption of the Cerro Negro volcano. National seismological experts, meanwhile, said they could not immediately confirm radio reports that the Momotombo volcano erupted Sunday, causing additional earthquakes. Authorities said 17 houses were destroyed Saturday in the town of Miralagos as a result of an earthquake caused by Cerro Negro's eruption. Only three people were wounded and no deaths were reported. The houses collapsed because of poor construction, including a lack of reinforcements and basic materials like iron, authorities said.
(CNN) The slopes of Mayon volcano in the Philippines bulged further on Thursday, suggesting growing pressure from inside the rumbling mountain in a prelude to a possible eruption, vulcanologists warned. Areas where the bulging have occurred "should be considered very hazardous," the Philippine Institute of Vulcanology and Seismology said. Mayon, located in Albay province 340 km (210 miles) southeast of Manila, has been rumbling since it exploded mildly on June 22, killing one villager.
SUVA, Fiji (AP) - Jet setters planning to greet the year 2000 on the Pacific island of Taveuni may want to think again - a geologist warned Tuesday the island is a sleeping volcano that could erupt any time. Known as the garden island of Fiji, 183-square-mile Taveuni is the third largest of Fiji's 360 islands. Scientific reports indicated Taveuni had erupted intermittently 300 to 400 years ago as a monogenetic volcano - with molten rock bursting to the surface in different places each time. Unlike traditional cone-shaped volcanos, monogenetic fields are collections of sometimes hundreds of separate vents and flows. Rather than a central eruption point, magma oozes from different vents and spreads over a wide area.
LEGAZPI, Philippines (AP) - A Philippine volcano briefly spewed thick smoke high into the air Tuesday, government officials reported, adding that it posed no danger to nearby residents. Mayon Volcano, one of the most active volcanoes in the Philippines, shot grayish smoke about four miles into the air. The volcano is in Albay province, 210 miles southeast of Manila. Disaster officials said there were no immediate reports of deaths or injuries. About 500 people moved out of their homes in farming villages on the volcano's slope to school buildings in a nearby town as a precaution. Mayon, a popular tourist attraction, last erupted in February 1993, killing at least 70 people
WASHINGTON (AP) - Volcanic rocks newly discovered in Brazil indicate that an eruption 200 million years ago produced the most widespread lava flow in Earth's history, splitting apart North and South America, Europe and Africa. Scientists say it may have caused a massive extinction at the same time. A previously unrecognized area of ancient lava flow covering about 965,000 square miles in the Amazon basin turns out to be related to lava flows on three other continents, researchers say in Friday's issue of the journal Science. The eruption occurred at the same time and had the same origin as lava flows found in North America, Africa and Europe, said Paul Renne of the University of California at Berkeley, who led the international team that conducted the research.
YAOUNDE, Cameroon (AP) - Fresh tremors shook villages around a fiery volcano in western Cameroon Wednesday, with geologists fearing that mounting lava flows could soon threaten nearby residents, local media reported. No damage was reported from the latest tremors, but geologists said a fifth vent in the cone may soon explode, adding to the lava flow from four vents that erupted Saturday. One tremor early Wednesday and another late Tuesday jarred the town of Buea, 13 miles south of Mount Cameroon, also known as Mount Faka. The 13,428-foot volcano is best known as a tourist attraction that draws thousands for an annual race up its black, rocky slopes. It began erupting over the weekend.
YAOUNDE, Cameroon (AP) - A plodding river of lava seared rain forests and threatened small farms in western Cameroon on Tuesday and new tremors forced hundreds to evacuate, state radio said. Many villagers who fled their homes when Mount Cameroon erupted near the Atlantic coast have returned, but lava will continue to flow into the coastal rain forest for days or weeks, Cameroon Radio Television reported. The 13,400-foot volcano, also known as Mount Faka or "Chariot of the Gods," began erupting over the weekend in this West African nation. Frequent tremors have rattled and damaged area houses.
YAOUNDE (Reuters) - Mount Cameroon volcano has erupted for the first time since 1982, causing damage but no known casualties, state radio reported Monday.
The eruption of the volcano, close to Cameroon's Atlantic coast, triggered lava flows late Sunday and an exodus of residents from nearby villages.
The volcano dominates the contested oil-rich Bakassi peninsula and is part of a geological faultline that runs through western Cameroon and Equatorial Guinea.
The local Bakweri people believe the mountain erupts when their gods and ancestors who inhabit it are angry or when a chief dies. They perform traditional rituals to appease them.
The radio reported that some houses, electricity poles, telephone lines and transmitters of Radio Cameroon's local Buea station were damaged.
It said that earth tremors preceded the eruption Saturday and Sunday. Reports from the region said that lava flows were heading west toward the Atlantic Ocean.
The volcano, which is nicknamed the chariot of the gods and is usually covered by thick cloud, has erupted eight times in recent history. In 1982 there were no casualties.
In 1986, toxic fumes linked to volcanic activity killed 1,746 villagers living around Lake Nyos, which is at the northern end of the faultline. Reports from the lake say gas levels have been rising again.
The volcano is also the site of an annual endurance race. This year's race took place on February 6.
The following was relayed by Dan Shackelford <danshack@ix.netcom.com>
Subject: FW: Indonesian update for Peuet Sague, Kerinci, Anak Kraktau,
Semeru, Batur, Sangeang Api, Lokon, Karangetan (Api Siau), Merpai,
Ibu
> From <http://www.vsi.dpe.go.id/hotnews.html>, the following Indonesian
> update is for 9-15 March 1999
> 1. G. Peuet Sague
> Volcanic activity was increasing during this week. Sufficient booming voice could be heard from Transmigration settlement about 20 times/day. Seismic recorded at G. Peuet Sague observatory declined compare to previous week.
> Specification of seismic recorded during this week can be seen on the
> table below:
> Events Last week This week
> Volcanic A 8 3
> Volcanic B 14 13
> Tectonic 6 3
> Emission 4 1
--------------------------------------------------------------------------
> 2. G. Kerinci
> Volcanic activities increased during the week. The ash plume rose 200-600 m above the summit, white to darkish in color.
> Seismicity data revealed decrease in number of volcanic and tectonic
> quakes compare to the week before.
> Details of seismic events during this week are listed below:
> Events Last week This week
> Volcanic A 3 2
> Volcanic B 4 1
> Tectonic 11 5
> Explosion - -
> Emission 368 343
> --------------------------------------------------------------------------
> 3. G. Anak Krakatau
> Activities of G. Anak Krakatau decrease early of this week. Weak booming voices heard twice at 1st and 2nd days, light plumes were unobserved. On the end of the week these booming voices were bare, and the light plume observed on March 14. A white-gray ash plume burst 100-300 m above.
> Considering the eruption type of G. Anak Krakatau as 1992-1997 features with 1-2 years interval of eruption period alternated with 1-1.5 years of eruptive quiescence, this activity assumed to be continue along this year.
> --------------------------------------------------------------------------
> 4. G. Semeru
> White-gray ash plume occurred, with 400 - 500 m heights above the summit. Some earthquake events were recorded, including debris events with maximum sliding distances of 2000 m. Seismic recorded during this week can be seen on this table:
> Events Last week This week
> Volcanic A 7 8
> Volcanic B 1 35
> Tectonic 9 27
> Debris 6 42
> Explosion 280 385
> Tremor 1 0
> --------------------------------------------------------------------------
> 5. G. Batur
> White emitted ash was observed, reached about 10-100 m heights above the crater. Booming voices were heard 6 times. Volcanic shocks record increase drastically compare to previous week.
> List of seismic recorded can be seen as follow:
> Events Last week This week
> Volcanic A 2 106
> Volcanic B 0 241
> Tectonic 1 1
> Emission 2 26
> --------------------------------------------------------------------------
> 6. G. Sangeangapi
> White ash plume rose 10-80 m above the summit. The seismograph was in reparation since February 21.
> --------------------------------------------------------------------------
> 7. G. Lokon
> White ash plume rose 25-75 m above the crater rim. During this week,
> shallow-volcanic events still recorded highly as well as deep-volcanic
> events, and the details are shown as follows:
> Events Last week This week
> Volcanic A 7 26
> Volcanic B 15 27
> Tectonic 34 27
> --------------------------------------------------------------------------
> 8. G. Karangetang
> Ash emission still identified from Main crater and II crater, light glowing
> sometimes observed at Main crater. Main crater produced white thick-medium ash plume, rose 500 m above the crater. Meanwhile, ash plume from II crater revealed as white thin-medium, rose 200 m above. Glowing light monitored about 25 m height inside the ash column.
Tectonic and multiphase shocks recorded slightly elevated compared to previous week.
> Earthquake recorded of G. Karangetang can be seen as follow:
> Events Last week This week
> Volcanic A 8 7
> Volcanic B 0 0
> Tectonic 151 203
> Multiphase 40 104
> --------------------------------------------------------------------------
> 9. G. Merapi
> A vigorous white ash plume, weak pressure, with 550 m maximum height above the summit were observed. Lava glowing still identified in the direction of K.Blongkeng, K.Lamat and K.Sat. Maximum sliding distance was 0.8 km. Glowing light on lava dome was unobserved.
> Small pyroclastic flow noted on March 11, in the direction of K.Blongkeng/K.Lamat/K.Sat with 0.8 km of sliding distance.
> Seismic activities dominated by multiphase events, assumed as the result of lava glowing debris. Small lahar flow revealed at K.Sat on March 13, no victims were reported.
> --------------------------------------------------------------------------
> 10. G. Ibu
> Field observation on March 11, 1999:
> Some eruption still occurred as well as rumbling noises, but the bigger eruption (accompany with booming and thick ash) already decreased, occurred every 15-20 minutes. At previous observation (February 2,1999) this happened every 5 minutes. Lava volume remains constant as the time before, but still exhibit as glowing one. Seismograph recorded still dominated by explosive shock, which are noted during this week occurred as 779 events (673 events at previous week).
> --------------------------------------------------------------------------
Scientists in Hilo, Hawaii, this week embarked on a scientific drilling project in an attempt to unearth the history of Hawaii's volcanoes. The Hawaii Scientific Drilling Project -- a cooperative research project involving the University of Hawaii; University of California, Berkeley; the California Institute of Technology and a team of earth science researchers from nearly two dozen universities and research institutes -- will travel a million years into the past by boring thousands of feet down into the volcanic island, according to researchers from the University of Hawaii.
Scientists on the big island of Hawaii will drill up to three miles beneath the surface to sample the lava flows that formed 14,000-foot Mauna Kea. By studying the sequence of lava samples, their chemical compositions, magnetic characteristics and isotopic compositions, researchers hope to uncover the planetary processes that produced the Hawaiian Island chain.
The project is the largest scientific drilling program funded by the National Science Foundation. In addition to revealing new clues about the origin of Hawaiian volcanism, it promises insights into volcanic hazards, the history of Earth's magnetic field and groundwater movement deep within the volcanoes, say University of Hawaii scientists.
The site -- an abandoned quarry located near the Hilo airport -- was selected because it is halfway between the Mauna Kea and Mauna Loa rift zones, reducing the likelihood of encountering intrusive lavas or hydrothermal alteration of the subsurface rocks. Either condition would produce undesirable characteristics in the samples, making the interpretation of their chemical compositions much more difficult.
Scientists will work two six-month drilling intervals using a coring system designed and fabricated especially for the project. The first coring effort is expected to begin in mid-March and site preparation and rig mobilization are underway. Program scientists hope to recover cores to a depth of about 8,000 feet during the initial drilling. The second drilling campaign, to begin in about three years, will push for 15,000 feet.
According to NSF, the primary scientific objective of the project is to learn more about the phenomenon known as mantle plumes, which are jets of very hot, solid rock material that rise through the interior of the Earth from a depth of almost 1,865 miles. Mantle plumes are believed to be responsible for the volcanism in Hawaii, which occurs in the middle of one of the large tectonic plates that constitute Earth's crust.
By studying the lavas of the Mauna Kea volcano, scientists hope to learn more about how mantle plumes originate and how magma makes its way to the surface. Because the lavas to be drilled vary in age from about 1,000 years at the surface to about a million years at 15,000 feet, the core samples will provide a nearly continuous record of the earth's magnetic field over this time interval. Project data will provide the most detailed record ever assembled of how the magnetic field changed over time, say scientists from UH.
VOLCANIC ASH ADVISORY
STATEMENT ISSUED 1900 UTC 18 MAR 1999 BY THE WASHINGTON VAAC
.
POPOCATEPETL 99-024 MEXICO 19.02N 98.62W
.
BACKGROUND: POPOCATEPETL MEXICO (1401-09) SUMMIT HEIGHT 17930 FT (5465 M)
.
SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL IMAGERY. MEXICO CITY
UPPER AIR SOUNDING.
.
MWO REPORT..
ERUPTION DETAILS: ERUPTION OCCURRED AROUND 18/1130 UTC
.
DETAILS OF ASH CLOUD: GOES 8 IMAGERY THROUGH 1815 UTC SHOWS THAT THE ASH PLUME
HAS BECOME VERY DIFUSE AND HARD TO DISTINGUISH FROM METEOROLOGICAL CLOUDS. THE
PLUME WAS LAST CLEARLY VISIBLE IN THE 1615 UTC IMAGE NEAR 22.1N 93.4W. BY FOLLOWING
THE CLOUD MOTION SIGNATURES AND USING EXTRAPOLATION THE POSITION OF THE ASH
PLUME AT 1815 IS NEAR 22.8N 91.8W.
.
TRAJECTORY: 1200 UTC MEXICO CITY SOUNDING SUGGESTS ASH BETWEEN FL350 AND FL400
WOULD MOVE TOWARD THE NORTHEAST AT ABOUT 65 KTS.
.
THIS AND OTHER VOLCANIC ASH ADVISORY STATEMENTS OFTEN ACCOMPANIED BY A MAP DEPICTING
ASH LOCATION ARE AVAILABLE AT INTERNET URL ADDRESS
http://www.ssd.noaa.gov/SSD/ML/vaacmsgs.html
CIUDAD GUZMAN, Mexico (AP) - Mexican authorities evacuated residents of eight hamlets near the flanks of the Colima volcano Sunday, while the smoking gray peak shuddered from a new round of explosions. The evacuations came four days after the volcano, which straddles the western Mexico states of Jalisco and Colima, shot ash into the air and spewed lava down its slopes. Officials fear a larger eruption. "Based on the moderate explosions ... the scientific advisory committee has decided to increase the security cordon to six miles" around the crater, the National Center for Disaster Prevention wrote in a press statement. The new evacuation order affects about 350 people.
(Nando Media) (Reuters
News Service) CATANIA, Sicily
(January 20, 1999 2:55 p.m. EST
http://www.nandotimes.com)
Mount Etna shook with a violent explosion Wednesday, sending a column of ash 16,500 feet into the air. Vulcanologists called the blast "brief yet very intense" but said there was no cause for alarm. "A strong explosion occurred around 12:30 p.m. from the southeast crater of Etna," Rome's civil protection department said in a statement.
"The phenomenon is part of volcanic activity happening since September, which has already provoked around 20 such episodes." Though vulcanologists saw no grounds for concern, "the almost total absence of wind allowed the column of ash caused by the explosions to rise to around 5,000 meters," the statement said. Etna, Europe's tallest and most active volcano, has been intermittently belching rocks, ash and lava since July, but experts have played down the risk of a big eruption.
The last major eruption was in 1992 when a heavy lava flow threatened to bury the town of Zafferana, on the 10,900-foot volcano's lower slopes. The U.S. and Italian military intervened with controlled explosions to divert the lava away from the town until the eruption ended.
Copyright © 1999
VESUVIUS HOME PAGE
We have recently added considerable new information to our Vesuvius home page
1. The Vesuvius Problem
(history, institutions, civil protection, VESUVIUS 2000, volcanologists, mass
media, European Union, etc.)
2. Cultural activities on the territory (public seminars, manifestations of
Vesuvius area schools, etc.)
3. Global Volcanic Simulator (concepts, state of the art in global simulation,
Vesuvius eruption forecasting, etc.)
4. Information for our Italian-speaking audience.
For additional clarifications,
please contact:
Prof. Flavio Dobran President,
Global Volcanic and Environmental Systems Simulation (GVES)
P.zza Matteotti, CP418, 80133 Napoli, Italy
dobran@idt.net
http://idt.net/~dobran
KVERT Update Alaska Volcano
Observatory INFORMATION RELEASE
99-3 KAMCHATKAN VOLCANIC ACTIVITY
Monday, January 18, 1999, 17:00 KST (0500 UTC)
The following Release was received by e-mail from KVERT (Kamchatkan Volcanic Eruptions Response Team). All times are Kamchatkan Standard Time (KST, 21 hours ahead of AST).
KLYUCHEVSKAYA GROUP OF VOLCANOES KLYUCHEVSKOY VOLCANO 56o03' N, 160o39' E; Elevation 4,750 m
CURRENT LEVEL OF CONCERN COLOR CODE IS YELLOW.
During the last week (January 11-17), seismicity at the volcano continued to be above background levels. On January 13, a 22-minute series of shallow earthquakes were recorded at the volcano and a fumarolic plume rose 100-200 m, extending 3-5 km to the southeast.
Since January 15, 00:55 AM (KST), a series of deep (25-50 km) earthquakes began to be recorded beneath the volcano.
On January 14, a fumarolic plume rose 50 m above the volcano.
On other days, the volcano was obscured by clouds.
SHEVELUCH VOLCANO 56o38' N, 161o19' E; Elevation 2,800 m
CURRENT LEVEL OF CONCERN COLOR CODE IS GREEN.
Seismicity under the volcano was about at background levels.
On January 13-14, a fumarolic plume rose 150 m above the volcano.
On other days, the volcano was obscured by clouds.
BEZYMIANNY VOLCANO 55O 58'N, 160o36'E
CURRENT LEVEL OF CONCERN COLOR CODE IS GREEN.
No seismicity was registered under the volcano.
On January 13-14, a fumarolic plume rose 100-300 m above the volcano, extending 3-5 km to the southeast.
The volcano was obscured by clouds the rest of the week.
KARYMSKY VOLCANO 54o03'N, 159o27'E; Elevation 1,486 m
CURRENT LEVEL OF CONCERN COLOR CODE IS YELLOW
Seismicity remains above background level. The low level strombolian eruptive activity that has characterized the volcano for two years continues.
About 200-300 earthquakes and gas explosions occur every day. Satellite imagery obtained by AVO on January 14 at 8:30 AM (KST) showed a strong thermal anomaly on the volcano. No change in seismicty was noticed.
AVACHINSKAYA GROUP OF VOLCANOES 153o15'N, 158o51'E;
CURRENT LEVEL OF CONCERN COLOR CODE IS GREEN
Seismicity at Avachinsky and Koryaksky volcanoes are at normal levels.
PLEASE CONTACT AVO IF YOU HAVE QUESTIONS OR COMMENTS.
Dr. Olga Chubarova
Kamchatka Volcanic Eruptions
Piip Blvd, 9 4200 University Drive
Petropavlovsk-Kamchatsky,683006,RUSSIA.
ivgg@svyaz.kamchatka.su
tel. (415-22)59385
Dr. Thomas P. Miller
Alaska Volcano Observatory Response Team, IVGG,
Anchorage, Alaska 99508
tmiller@tundra.wr.usgs.gov
tel. (907)786-7454
White Island Update SCIENCE ALERT BULLETIN
January 18 1999 (Monday) 1130 NZDT (UT +13) WHITE ISLAND VOLCANO Update
Eruptive activity is continuing at White Island, with explosive eruptions from Metra Crater on Saturday and steam-gas emissions from PeeJay Vent. Volcanic tremor levels were low between January 11 and 13, before dramatically rising to peak overnight January 14-15 at the highest levels since those that accompanied the formation of the Metra Crater on January 6-7 (Fig.1). A further peak occurred on the evening of January 15. Between 1030 and 1500h on January 16 (Saturday), explosive activity occurred from Metra Crater, tossing blocks up to 400 m from the crater. Observations from a helicopter operator who was over the island 1200-1220h suggest multiple vents were active, each one erupting differently. Volcanic tremor levels reached a low on the morning of the 17th and are now slowly increasing. Observations on Sunday confirm that no eruptions were occurring from Metra Carter, with overnight rains having flooded the crater floor. PeeJay Vent was producing a steam column to about 600m. Some collapse has also occurred about the margin of 1978/90 Carter. Figure 1: Seismic energy levels, January 1999. In summary, eruptive activity continues at White Island. The level of eruptive activity has varied with time, and is now characterised by explosive events. The current level of eruptive activity confirms an Alert Level of 2. We anticipate that the current style of eruptive activity may continue for some time and will vary in intensity with time. Brad Scott Mgr Volcano Surveillance
You wanted updates, well have we got updates.
Let's just get right into it then. All of the updates have been added to VolcanoWorld's Current Eruptions section.
Our first update is of
recent activity at Colima, Mexico. To view this update, please visit:
http://volcano.und.edu/vwdocs/current_volcs/mexico/colima.html
Our next update is a new
page covering the recent activity at Terceira, Azores. To view this update,
please visit:
http://volcano.und.edu/vwdocs/current_volcs/africa/terceira.html
The next update is of the
recent activity at White Island, New Zealand. This update can be viewed at:
http://volcano.und.edu/vwdocs/current_volcs/new_zealand/white.html
Next our update covers
recent activity at Guagua Pichincha, Ecuador. To view this update, visit:
http://volcano.und.edu/vwdocs/current_volcs/ecuador/guagua_pichincha.html
Our final update is of
the recent activity at Montserrat, West Indies. This update can be viewed at:
http://volcano.und.edu/vwdocs/current_volcs/montserrat/
-Dan
******************************************************************************
**Eruption Update list courtesy VolcanoWorld, http://volcano.und.edu * *
To POST a message, send it to eruption-update@volcano.und.edu * *
QUESTIONS ABOUT VOLCANOES should be directed to Ask A Volcanologist * *
-QUESTIONS ABOUT THE LIST itself should be directed to * * owner-eruption-update@aero.und.edu. * ******************************************************************************
SALEM, Montserrat (AP) - Scientists still believe the volcano on the Caribbean island of Montserrat is settling down, despite an eruption that sent ash 20,000 feet into the air a day ago. The Wednesday morning eruption sent an avalanche of hot gases and rocks down the eastern flank of the Soufriere Hills Volcano but did not affect inhabited areas, Sue Loughlin, deputy chief scientist at the Montserrat Volcano Observatory, said Thursday. She said it was smaller than an eruption in November and was mostly confined to the southern two-thirds of the island, which have been evacuated.
Mount Etna, Europe's tallest and most active volcano, spewed out yet another flow of lava, rocks and ash, illuminating the night sky on Sunday. The latest round of activity from the 11,000-foot (3,300-meter) volcano posed no danger to residents of towns on the lower slopes, according to officials at Catania Vulcanology Institute in Sicily. The volcano's explosions, from its southeast crater, shot red volcanic ash and rock 600 feet (200 meters) into the night sky. The explosions lasted about four hours and were accompanied by minor seismic activity. Ash fell near the village of Fiumefreddo, east of the volcano. Etna's last major eruption came in 1992, when a large lava flow threatened to bury the town of Zafferana on the volcano's lower slopes. The U.S. and Italian military intervened with controlled explosions and the construction of concrete barriers to divert lava away from the town.
WASHINGTON (Reuters) -- The United States on Thursday warned Americans traveling in Ecuador to beware of a big rise in activity at the nation's Guagua Pichincha volcano. The State Department said the U.S. embassy in the capital Quito reported that the volcano, located west of the capital, "exhibited a significant increase in the number of tremors and an accompanying rise in magma," a pasty mixture of crude minerals, in recent months. "The volcano has continued to exhibit anomalous activity," with a series ofintermittent explosions, including one on December 23, the second largest since the unusual activity was first recorded in August, it said. The department noted that the Quito city government issues daily reports on the volcano. "Travelers in Ecuador are advised to pay close attention to the news media in Quito for updates," the department said.
Summary
Minor eruptive activity is now essentially continuous at White Island. There is evidence that molten magma is now being tapped directly to drive the eruptive activity, although only very weak volcanic tremor accompanies the current ash eruptions. A surveillance visit was made on Tuesday December 1 to assess the ongoing activity, conduct deformation and magnetic surveys, and collect ash and gas samples. The results available to date from that visit are reported below.
In summary, minor eruptive activity continues at White Island. The level of activity has varied with time, however the level of current activity and volcanic indicators are now sufficient to raise the Alert Level from 1 to 2. The current style of activity may continue for some time and will vary in intensity with time.
Observations
The active vent at the base of the NW wall of 1978/90 Crater continues to erupt fine grained volcanic ash. The vent size has not changed since the November visit. During our visit an ash-charged, tan-brown, convecting plume was being emitted from the vent and rose to about 800m before trailing off down wind for 10-15km. The volume of ash contained in the plume was greater than observed over the past month. The eruptive activity over the previous month has deposited up to 45mm of fine dark grey and brown volcanic ash at the crater rim. Samples of ash falling on 1 December 1998 showed a significant change from ash collected on 23 November 1998 and earlier. The 1 December ashes contained fresh, vesiculated glass, suggesting that molten magma may have risen in the vent and is now contributing directly to the eruption discharge. Previously the ash was derived from solidified lava covering the magma.The ground deformation survey shows a consistent trend of minor inflation across the main crater floor, with continued subsidence near the rim of 1978/90 Crater, (Fig. 1). Shown in figure 2 are time series plots for four selected marks, the large scale inflation post 1990 is evident at the more distal sites (Pegs C and J) with only minor changes over the last 2-3 months. A small scale deflation-inflation event occurred 1996-97. Collapse about the crater rim which started in July is continuing, but now at a lesser rate (Pegs M and W). The provisional results from the magnetic survey indicate heating at depth, with shallow cooling about the crater rim area.
56o03' N, 160o39' E; Elevation 4,750 m
Current level of concern color code is Yellow. During the last week (December 21-27), hypocenters of earthquakes were concentrated at two levels: near the summit crater and at depths of 25-30 km. On December 21, the fumarolic plume rose 100 m above the crater, extending 10 km to the northwest. On other days, the volcano was obscured by clouds. On December 23, at 23:52 (KST), a series of shallow earthquakes of M<=2 began to be recorded up to distances of >100 km. On December 24, at 04:00 (KST), the activity abruptly decreased although still slightly above background levels through the end of the week. Satellite images obtained during and after the aforementioned time interval indicate no large areas of airborne ash.
Karymsky Volcano is also at code Yellow. 54o03'N, 159o27'E; Elevation 1,486 m Seismicity remains above background level. The low level strombolian eruptive activity that has characterized the volcano for two years continues. About 300-400 earthquakes and gas explosions occur every day.
The lava flow continues descending on the SW flank. Its distal front has reached an approximate altitude of 2,550-2,450 m, and has a length of ~2,350 m. It has covered the 1991 lava flow. The 1998 lava flow is about 2-3 times wider than the 1991 one. The latest cospec measurement was performed on December 11, resulting in 2,880 +/- 727 t/d. Both number and size of rockfalls and small block-and-ash flows have showed a marked decrease.
The Civil Protection authorities and the Mexican Army mantain a group of soldiers and trucks at the town of La Yerbabuena (7.7 km from the dome) in order to make an eventual evacuation. The Grupo de Informacion del Observatorio Vulcanologico de la Universidad de Colima keeps visiting the inhabitants of the town to communicate to them the features of the volcano's activity, as well as to answer the related questions of the public.
http://www.volcano.si.edu/gvp/gvn/activity/gvn00037.htm
MEXICO CITY (AP) - The Popocatepetl volcano erupted Thursday night, tossing red-hot rocks as far as two miles that set off brush and forest fires on its slopes. The volcano's burst also sent a column of ash and vapor three miles into the air, the National Center for the Prevention of Disasters reported. TV footage showed the peak covered by embers emitting a red glow into the sky. The fires on the volcano's slopes burned for hours. There were no immediate reports of injury or property damage. The Popocatepetl volcano has been spitting vapor, ash and rock intermittently since 1994, after lying largely dormant since 1927. The volcano lies 50 miles southeast of Mexico City and 300,000 people live on its slopes.
Volcano Index
(CNN) A thick plume of ash and smoke belched skyward Monday, as Mexico's giant Popocatepetl volcano rumbled for a fifth day. Nearby residents waited again for a signal that they would be evacuated, but disaster officials said there were no immediate plans for evacuation. Some 70,000 people who live on the mountain's flanks are on alert. The 17,992-foot (5,452-metre) volcano located near Mexico City sent smoke several miles (kilometers) into the air and spread a blanket of lava and fiery rocks around the peak.
Volcano Index
MEXICO CITY (Reuters) - Civil defense authorities in Mexico remained on maximum alert Thursday with the country's "Volcano of Fire" still threatening an eruption. Meanwhile Popocatepetl, Mexico's most famous volcano, started to stir on the edge of Mexico City. Located on the border between Mexico's Jalisco and Colima states, the "Volcano of Fire" has exhibited increasingly threatening behavior over the past three days. Authorities have evacuated two villages, one in each state, and plans to return the inhabitants to their homes Thursday were shelved when seismic activity intensified.
Volcano Index
OLVESTON, Montserrat (Reuters) - A massive ash cloud rose some 20,000 feet over Montserrat Thursday as a dome of material in the volcano partially collapsed, sending hot rocks and gas racing down its flanks. There were no reports of injuries, but the wind spread the ash over much of the island. The "exclusion zone," roughly the southern two-thirds of Montserrat, has been evacuated for much of the time since the British territory's volcano roared to life in July 1995 after nearly four centuries of dormancy. The island's population has dropped from about 11,000 before the first eruption to about 3,000 people, who are restricted to the northern "safe" zone.
Volcano Index
CATANIA, Italy (Reuters) - A new flow of lava emerged from Mount Etna Sunday but officials said there was no immediate danger to residents on the slopes of Europe's most active volcano. Officials said the lava flow was several hundred yards long and old, dry, cold lava was absorbing or slowing it. The new lava from Etna, which has been in minor activity for months, following a spate of 12 earthquakes inside the volcano since Saturday. Most of the earthquakes, which registered as much as 2.6 on the Richter scale, were detected only by instruments and not felt by residents. In the past few months Etna has at times belched rock and ash visible for miles. Etna's last major eruption was in 1992, when lava threatened the village of Zafferana.
Volcano Index
GOMA, Congo (Reuters) - Lava flowing from a volcano in eastern Democratic Republic of the Congo is lighting up the night skies of Goma and causing concern for rebels fighting President Laurent Kabila and his allies. The Nyamuragira volcano, just north of Goma, has gently gushed lava from its cone and through a fissure in its side since Oct. 17, a senior official at the National Scientific Research Center in Goma said. Residents said light from the 9,932-foot high volcano had decreased in recent days, but Monday night a red glow was visible north of town.
Volcano Index
SAN JUAN, Puerto Rico (AP) - Worried that a spate of tiny earthquakes may indicate volcanic activity, the Caribbean nation of Dominica is developing an emergency management plan, an official said Monday.
Tremors have occurred daily since late September, most of them too small to be felt. But on Friday, there were about 200, including a cluster that caused small landslides, said Cecil Shillingford, assistant national disaster coordinator.
The tremors' relative shallowness - 1 to 3 miles below the Earth's surface - have scientists concerned they might signal an eruption of one of Dominica's dormant volcanoes.
Lawmakers were to consider Tuesday a disaster plan for an eruption, Shillingford said. Cabinet members ordered the plan be drafted during an emergency meeting Friday.
"We are doing it as a precaution," he said. "We don't know what this means yet. It has happened in the past and nothing has happened."
The cluster that hit shortly after 3 a.m. Friday sent boulders and dirt tumbling onto roads leading to Pointe Michel, Soufriere and Scott's Head on the southwest coast.
Volcano Index
MEXICO CITY (Reuters) - Mexico's Popocatepetl volcano rumbled and spewed ash Tuesday that could fall on Mexico City if prevailing winds do not change, the country's interior ministry said. The ministry said, however, that the volcano remained stable and the government's amber warning alert remained in effect. A red alert would force the evacuation of nearby villages and towns. The 17,992-foot volcano, whose name means "smoking mountain" in the Nahuatl Indian language, lies 40 miles southeast of the capital and has been threatening an eruption for years. In June 1997 it covered Mexico City with a thin film of ash and temporarily closed the international airport.
CATANIA, Italy (Reuters) - A series of volcanic explosions shook the summit of Mount Etna Friday, but vulcanologists said the increased activity over the past two days did not mean an imminent violent eruption. Massimo Pompilio, a researcher at the vulcanology institute in Catania, said the increased activity did not signal a major eruption, adding it was not as intense as that seen in late July. At that time, Etna spewed rocks and ash up to six miles away, provoking concern it might be on the verge of its biggest eruption since 1992 when two streams of molten lava threatened Zafferana, a village of 7,000 on its lower slopes.
Southwest Volcano Research Center As of the 15th of September, it has been reported directly to SWVRC that confirmation of an eruption of Batur last July has been received. During the first week of July, Batur continuously emitted a gray plume 25-300 m above the crater. Observers saw incandescent material frequently ejected. Two episodes of tremor with amplitudes of 0.3-24 mm were recorded.Batur caldera lies in the NE portion of Bali Island, about 70 km N of the capital city of Denpasar. The caldera contains an active, 700-m-tall stratovolcano rising above the surface of Lake Batur. Batur has erupted frequently (over ~20 times) since the 1800's, generally producing Strombolian emissions and lava flows.
QUITO, Ecuador (AP) - A volcano has begun erupting on one of the Galapagos Islands, but none of the inhabitants, or unique animal species, on the island are in any immediate danger, authorities said Wednesday. Cerro Azul volcano, on the island of Isabela, began erupting Tuesday night. Isabela has about 1,000 inhabitants and is the largest island in the Galapagos archipelago, located 600 miles west of Ecuador's mainland. The nearest populated center to the volcano is the village of Puerto Villamil, 30 miles away. "There is no danger to the population. The only danger is that because of drought conditions the eruptions could start a fire that could affect the native turtles," Lt. Angel Moreno said. Island authorities have declared a state of emergency on Isabela island as a precautionary measure.
MEXICO CITY (Reuters) - Mexico's "smoking mountain" Popocatepetl sprayed nearby communities with a light shower of gray ash Tuesday after a minor eruption lasting more than 20 minutes, emergency services said. The Civil Protection service said "Popo," as the volcano some 33 miles southeast of Mexico City is commonly known, belched steam, gas and ash at 5:39 a.m. "A light rain of ash fell south of the volcano," the service said in a recorded message. It said the eruption, which lasted 21 minutes, was of moderate intensity. The volcano has been fairly active for several years. The Civil Protection service said an amber warning alert remained in effect. A red alert would force the evacuation of nearby villages and towns.
On Friday August 21
a steam and gas plumes were reported above White Island and since then several
reports of ash fall have also been received. As a follow on to these reports
a surveillance visit was made on Monday August 31. Observations from that visit
confirm minor eruptive activity has recommenced at White Island and the Alert
Level is now raised to Level 2.
A new active vent has been established in the northwestern corner of the 1978/
90 Crater Complex, in an area which has been characterised by high temperature
fumaroles and gas vents over the last 2-3 years. This vent is approximately
in the same area as a vent which formed in May 1991. A maximum temperature of
463C was obtained on the venting ash column at point of discharge. The progression
from high temperature fumarole, to active vent and eventually active crater
is a common process at White Island. The lake on the floor of 1978/90 crater
was greenish-brown in colour, and cool (20C) with no visible upwellings.
Brad Scott
Mgr Volcano Surveillance
Photos on www.gns.cri.nz
Mexico's towering Popocatepetl volcano erupted late Sunday night, sending a column of ash, steam and incandescent rocks soaring 3 miles (5 km) above the suburbs of Mexico City. No damage or injuries were reported from the 15-minute eruption. The activity followed a series of volcanic tremors that rumbled beneath the 18,000-foot mountain over the weekend. Popocatepetl lies about 38 miles (60 km) southeast of the Mexican capital. (Volcano World)
Mount Etna spewed rocks and ash as far as 6 miles Thursday and an expert said the Sicilian volcano could be on the verge of its biggest eruption for six years. "Etna is ready. An eruption like the one in 1992 is possible," said Letterio Villari, head of the vulcanology institute in the Sicilian city of Catania. In that year, molten lava from the volcano threatened a village on its slopes, and forced Italian and U.S. troops to divert the flow with man-made explosions. Italian TV showed red and orange rocks bursting into the air Thursday. (Reuters)
Authorities fearing an eruption evacuated more than 6,000 people over the weekend from the slopes of Indonesia's most active volcano, Mount Merapi, the Kompas daily reported Monday. The evacuation of the residents of eight villages, the first during Merapi's recent bout of activity, was ordered by local disaster coordination authorities despite the volcano still being rated one level below the maximum alert status, Kompas said. Village authorities said they arranged the evacuation of people to nearby village meeting halls after hearing automatic sirens that are designed to raise the alarm when the volcano's activity reaches a certain point. (Reuters)
The Soufriere Hills volcano erupted Friday, sending a massive cloud of ash thousands of feet into the air and flows of hot rock and gas down the mountain's flanks. Scientists at the Montserrat Volcano Observatory warned the volcano's dome, a mound of debris in its crater, was unstable and told residents of the Caribbean island to stay away from the rumbling mountain. The eruption,the largest in more than six months on the volcano-ravaged island, blasted ash some 45,000 feet into the air and dumped debris across the 39-square-mile British colony. No injuries were reported. Most of the island's remaining residents live in the northern "safe zone". (Reuters)
ALASKA VOLCANO OBSERVATORY
INFORMATION RELEASE
Tuesday, June 30, 1998, 1:00 pm ADT (2100 UTC)
KOROVIN VOLCANO
52°23’ N 174o09’ W
summit elevation 1533 m (~5029 feet)
At about 10 am ADT this morning, AVO received a report of an eruption of
Korovin volcano from a ground observer in the village of Atka. The crew of a
Coast Guard C-130 confirmed a plume to 16,000 feet ( 4877 m) ASL at 10:30 am
ADT. Local winds at the time were light and to the south southwest, and a dusting
of ash was reported in Atka. The low level ash and steam plume was not visible
in satellite imagery. Korovin volcano is located on the north end of Atka
Island in the central Aleutians, 538 km (334 miles) west of Dutch Harbor. It
is 21 km (13 miles) north of the village of Atka, population about 100. Korovin
is a 1533-m-high (5029 ft) stratovolcano with a basal diameter of 7 km (4 miles).
The last reported eruption was in March, 1987. AVO does not maintain seismic
monitoring equipment on Atka. AVO will continue to monitor the situation closely
using satellite and field observations.
Hi Folks, there has been an alarming increase in volcanic activity in Yellowstone Park. Click on the url below for a full story. Mitch Yellowstone
CATANIA, Sicily (AP) -- The crater area of Mount Etna has been closed to tourists after the volcano belched lava. The Italian news agency ANSA said Sunday that only those authorized to work near the summit were allowed near the crater. Etna's last major eruption was six years ago. There was very little earthquake activity, ANSA said, and no evacuation of the villages along the mountainside was announced. The volcano has been particularly noisy and active off and on since January, and lava has been running down the southeast slope.
The level of earthquake activity at Mount St. Helens has been gradually increasing over the past several months and accelerated during May. Rates of activity have gone from an average of ~60 well located events per month last winter to 165 events in May. Most of these recent earthquakes are very small with only 3 events larger than magnitude 2. The largest earthquake was on May 1 with a magnitude of 2.2. These earthquakes are occurring in two clusters directly beneath the lava dome in the crater. One cluster is in the depth range of 2 to 5 km below the dome and the other is in the depth range of 7 to 9 km. Almost no events have been located in the very shallow region of 0-2 km below the dome. None of these earthquakes are low-frequency, volcanic events that typically occur as precursors to major eruptions.
(AP) - The Pacaya
volcano spewed ash and fine granules of lava more than 6,000 feet into the air
Wednesday, coating nearby Guatemala City with a half-inch of gray grit. Authorities
declared an emergency in the towns around the base of the 8,420-foot volcano,
15 miles south of the capital and prepared for a possible evacuation. The clouds
of ash and black particles reduced visibility and forced Guatemala City's international
airport to close Wednesday afternoon. The capital's 2 million residents
covered their faces with handkerchiefs and improvised masks. Pacaya is the most
active of Guatemala's 32 volcanoes, with three lava flows formed in eruptions
between 1989 and 1991. The most recent eruption occurred in Nov. 1996, when
several hundred people fled their homes or were evacuated from villages because
airborne ash and lava flows. Wednesday's ash shower was fairly normal for the
volcano, which has erupted 29 times since the year 750. (Reuters)
Locataion: 14.4N,
90.6W
Pacaya has erupted several times during the period between May 15 may May 18.
These eruptions consistently ejected smoke and ash up to 1000 ft (~300 m) into
the air. Ash from these eruptions, combined with forest fires that have been
burning out of control for weeks in Central America, is causing serious problems
over Central America and Texas. The ash has made air travel difficult in many
areas, making landing possible only through the use of instrument guidence in
Guatemala City. Hondurus was forced to close its two largest airports. The ash
has also caused problems breathing as far away as Houston, Texas.
Costa Rica's Arenal volcano erupted Tuesday, spewing out lava and forcing the evacuation of two nearby villages, officials said. A powerful explosion shook the volcano, some 100 miles northwest of the capital San Jose, at 1 p.m., sending a column of hot ash and gas into the air, the officials said. No one was injured by the blast. Officials put the area on red alert, evacuating the hamlets of Tabacon and El Castillo and banning tourists from visiting the volcano. Geologists from Costa Rica's Volcanologic and Seismologic Observatory were flying over the area to check the volcano. Geologists fear the eruption may have opened a fissure on the north side of the volcano that is allowing lava to escape. (Reuters)
An airline pilot has reported a volcano erupting in Indonesia's north Sumatra province of Aceh, the official Antara news agency reported on Monday. It said Captain Hartono of national airline Garuda saw Mount Peut Sagoe erupting as he flew over it at a height of 24,000 ft. (7,315 meters) Sunday morning. The 2,790-meter volcano last erupted 70 years ago and spilled lava into surrounding uninhabited forests. Antara said there were three active volcanoes in Aceh, including Mount Peut Sagoe, which need constant monitoring. The other two are Mount Seulawah Agam and Mount Burni Telong. No further details were available. (Reuters)
An active volcano east of Mexico City belched smoke, ash and molten rock high
into the sky Tuesday, causing fires on its wooded slopes, authorities said.
At 11:07 a.m., "there was a puff of smoke that lasted more than five minutes
and which produced a cloud of ash more than fourkilometers (2.5 miles) high,"
said the Mexican Center for the Prevention of Disasters in a statement. There
were no injuries reported, although the eruption threw small burning rocks that
caused fires in fields and shook windows in nearby towns. The volcano Popocatepetl,
means"smoking mountain" in the local Nahuatl Indian tongue, is 17,992
feet high and sits 40 miles east of Mexico City. (Reuters)
Mexico's towering Popocatepetl volcano has spewed a new column of hot ash and gas in one of its most intense recent signs of activity, but officials did not believe a major eruption was about to occur.
Mexico's Center for Disaster Prevention said Wednesday the 17,992-foot snow-capped volcano released a thick cloud of ash Tuesday that rose more than a half-mile early in the day.
It said there was no sign the volcano's activity was becoming dangerous or heralded a major eruption. Popocatepetl, which means the "smoking mountain" in an ancient native tongue, erupted 31 times in 1997. (Reuters)
Volcano Index
Feb. 3 — A mile beneath the gray surface of the Pacific, a volcano pours lava into the black, almost freezing waters of the sea floor. The Axial Seamount, 300 miles west of Oregon’s coast, is erupting.
The eruption began Jan. 29. Hydrophones picked up the rumbling of the mountain as wave after wave of red molten rock oozed from its flanks.
Scientists recorded 7,000 earthquakes in the first four days. The eruption subsided, but the volcano, shaped like a giant turtle, continued to shake 20 to 30 times an hour. The volcano’s lava congeals almost immediately into smooth flows or rounded forms that resemble enormous marshmallows. Dark plumes of hot water roil up toward the surface.
A comparable event on land is the Kilauea volcano on Hawaii’s Big Island, where hot lava sizzles into the sea. Lava from the Axial Seamount flows across barren rock, populated only by small communities of peculiar sea life—huge red-fringed tubeworms, spindly white crabs and elongated clams. Such creatures survive the dark and cold by living around hydrothermal vents, the tall, gnarled chimney-like formations that spew hot mineral-rich water. (ABC News)
Volcano Index
Italian experts are trying to determine whether 200 small earthquakes that shook the slopes of Mount Etna last month were advance warnings of the volcano's first significant eruption in 6 years.
Scientists at the Institute of Volcanology in Catania said the quakes which hit Europe's tallest and most active volcano are the latest sign Etna's magma is moving perilously.
To see exactly how much, teams from the institute are trekking daily up the 10,900-foot mountain to take hundreds of new measurements of the volcano's surface. The expeditions are expected to continue for the next 2 weeks. (Reuters)
Volcano Index
Mexican authorities have decided to relocate some 20,000 people from their homes near the slopes of the rumbling Popocatepetl volcano, a news report quoted officials as saying Friday.
Officials have also decided to build giant walls along the volcano's slopes to help contain lava and mudslides in case of a major eruption, Televisa television network reported. The program, due to begin next week, would rebuild people's homes as close to their existing communities as possible, the network said.
In some cases, residents would only move to a higher part of their same town. (Reuters)
Mexico's majestic Popocatepetl volcano boomed out a loud eruption Thursday, spewing out a massive gas cloud and setting off a series of tremors reaching up to 3.3 on the Richter scale, local media reported. Television Azteca showed video of a giant cloud extending some four miles above the peak, which is 17,992 feet above sea level.
A massive explosion of Popocatepetl would be a major disaster for the 500,000 people who live in its shadow, and could pose a threat to the 18 million people living in Mexico City, just 40 miles away. 1/2/98 (Reuters)
(Reuters) One of the most active volcanoes in Russia's Far East region of Kamchatka began erupting Friday for the second time this year, spewing a column of ashes into the sky, the Emergencies Ministry said.
The Bezymyanny volcano started erupting after seismic activity in the Bering Sea off Kamchatka's eastern coast. An earthquake registering 5 on the Richter scale was detected in the early hours. The column was 5 miles high. "The people in nearby settlements are in no danger. The closest is about 40-50 miles away from the eruption site," an official said. U.S. satellites registered the plume of ashes as 60 miles long.
Volcano Index
By: Larry G. Mastin, WATER FACT SHEET: USGS Open-File Report 93-445
Volcanic eruptions are renowned for their violence and destructive power. This power comes ultimately from the heat and pressure of molten rock and its contained gases. Therefore we rarely consider the possibility that meteoric phenomena, like rainfall, could promote or inhibit their occurrence.
Yet from time to time observers have suggested that weather may affect volcanic activity. In the late 1800's, for example, one of the first geologists to visit the island of Hawaii, J.D. Dana, speculated that rainfall influenced the occurrence of eruptions there.
In the early 1900's, volcanologists suggested that some eruptions from Mount Lassen, Calif., were caused by the infiltration of snowmelt into the volcano's hot summit. Most such associations have not been provable because of lack of information; others have been dismissed after careful evaluation of the evidence.
The types of eruptions most likely to be influenced by weather are small ones that expel only rock fragments entrained in steam or magmatic gas, and no new lava.
In at least one series of such eruptions, at Mount St. Helens, Wash. between 1989 and 1991, an association with rainfall has been statistically documented.
THE GAS ERUPTIONS OF 1989-91: SMALL BUT POTENTIALLY DEADLY
Between August 1989 and June 1991, after nearly 3 years of quiescence, Mount St. Helens produced 6 small eruptions of gas and pulverized debris from the still-hot lava dome.
On 22 more occasions, seismographs recorded shaking of the sort associated with gas eruptions. During 4 of these 22 events, observers verified that no eruptions had occurred. The remainder took place when the dome could not be observed, though later visits found no new ash or other evidence of eruptive activity.
Some blasts were powerful enough to hurl blocks of rock a meter (3 feet) in diameter as far as a kilometer (0.6 mile) from the vent and to destroy three nearby seismic stations.
Plumes of ash that wafted up to 5 kilometers (3 miles) above the crater floor were carried by wind nearly as far as Yakima, Wash., 140 kilometers (90 miles) away, and in one case prompted flight cancellations at the Portland, Oreg. airport. Within the crater, debris was ejected or avalanched northward onto the crater floor. Some of the hot ejecta mixed with snow and produced small floods or slurries of rock and water (termed debris flows) that flowed out of the crater.
Compared with the eruptions of the early 1980's these events were small, but had there been visitors in the crater the eruptions could have been deadly.
In January and March 1993, eight volcanologists and three tourists lost their lives in two similar explosions in South America: at Galeras Volcano in Colombia and Guagua Pichincha Volcano in Ecuador. Another explosion of this type killed nine tourists on Mount Etna, Italy in 1979.
Small gas eruptions are potentially deadly because they are hard to predict.
Between 1981 and 1986, magmatic eruptions at Mount St. Helens were preceded by uplift of the crater floor and by earthquakes. In nearly all of those cases, scientists accurately predicted eruptions a few days to a few weeks in advance. No such precursors preceded the gas eruptions in 1989-91.
THE ASSOCIATION WITH STORMS
At Guagua Pichincha and Mount Etna, scientists suggested that the deadly explosions were associated with rainfall although they did not have enough information to document it.
At Mount St. Helens, the association is well documented. Of the six confirmed eruptions, all took place within 3 days after a major storm. The eruptions not only followed individual storms, they also tended to occur after sequences of storms lasting many days to a few weeks.
Statistical tests show that the chances are very small (one in many thousands) that this correlation is coincidental. Of the remaining 22 explosion-like seismic events, most (but not all) also followed storms.
WHAT IS THE CAUSE?
Seismic and other evidence show that the source of gas in the Mount St. Helens eruptions came from well below the dome. An increase in earthquakes below the volcano between 1987 and 1990 may have been an indicator of this rising gas. The gas presumably ascended to the base or interior of the lava dome and discharged explosively following storms.
How could rainfall have caused the release of this gas?
A little information on the dome might provide some clues. From magnetic measurements, we know that the interior of the dome is still hotter than 350 C (650 F)--hot enough to ooze like warm tar--even though the outer several tens of meters of the dome has solidified.
Over time, the dome cools from the outside inward. As it cools, the rock shrinks, fractures, and opens pathways to greater depth. Cooling and fracturing take place primarily during storms when water flows into the dome.
At the surface the pervasive growth of cooling fractures has caused entire outcrops to disintegrate to piles of rubble. Cooling fractures also reduce the strength of rock masses that cling precariously to the dome's slopes, promoting slides and avalanches of debris.
Between 1989 and 1991, large avalanches removed massive amounts of rock from the vent area. Much of the avalanching appears to have occurred during eruptions, although it is not known whether the eruptions caused the avalanches or vice versa.
One could speculate at least two ways that rainfall could have caused these eruptions. First, during storms, some fractures may have opened pathways for the release of pressurized gas from within or below the dome. Second, storms may have triggered rock slides or avalanches that exposed zones of pressurized gas. In either case, the infiltration of water into the dome probably acted to open some escape route for gas that was already present.
COULD IT HAPPEN AGAIN?
As of mid-1993, earthquake activity that peaked in 1987-90 below Mount St. Helens had decreased nearly to pre-1987 levels. If, as suspected, these earthquakes signalled the rise of gas that caused the eruptions, then new eruptions are not likely to occur in the near future. Beyond mid-1994, the likelihood of future eruptions is unknown. Mount St. Helens is still active and potentially dangerous.
FURTHER READING
Mastin, Larry G., 1994, Explosive tephra emissions at Mount St. Helens, 1989-1991: The violent escape of magmatic gas following storms?: Geological Society of America Bulletin, V. 106, p. 175-185.
For further information, contact: U. S. Geological Survey, Cascades Volcano Observatory, 5400 MacArthur Blvd., Vancouver, WA 98661 tel. (206) 696-7693. Open-File Report 93-445 /L.G. Mastin, 1993
Volcano Index
The summit of the Mount Etna volcano on the island of Sicily, Italy, one of the most active volcanoes in the world
Etna is one of the best-studied volcanoes in the world and scientists are using image to identify and distinguish a variety of volcanic features.
Etna has erupted hundreds of times in recorded history, with the most recent significant eruption in 1991-1993.
Scientists are studying Etna as part of the international "Decade Volcanoes" project, because of its high level of activity and potential threat to local populations.
Etna is one of the largest European continental volcanoes. The base of the volcano is about 36 by 24 miles (60 x 40 km). Below an elevation of about 9,500 feet (2,900 m) Etna is a shield. The upper 1,200 feet (400 m) is a stratovolcano made of several coalesced vents.
Much of the surface of the volcano is covered by historic lava flows. Most eruptive products are made of andesite. The eruption rate of Etna is about one-sixth that of Kilauea.
July 31, 1997, Etna Lava began to overflow from the northeast crater on July 23. This flow moved more than 0.6 miles (1 km) to the east, inside Valle del Bove. The flow was expanding at a rate of 10.6 ft3/s (0.3m3/s). The temperature of the flow is about 1980 degreesF (1080 degrees C).
This flow ceased on July 29, but the flow inside the Voragine crater is continuing. This information was summarized from a report from Ed Venzke to the Volcano ListServe.
July 19-20, 1997, a small amount of lava overflowed from SE Crater at Etna on the nights of July 19-20.This is the first time lava has flowed from that crater since 1990.
Volcano Index
Kilauea is the youngest of the subaerial volcanoes on the Island of Hawaii and lies at the southeast end of the Hawaiian chain.
Much of the bulk of the volcano is below sea level. The present-day caldera formed in 1790 A.D. and contains a pit crater, Halemaumau.
Two rift zones extend to the east and southwest. Kilauea is in the shield-building stage and is one of the most active volcanoes on Earth.
Over 90 percent of the surface is covered by lava less than 1,000 years old. The current eruption of Kilauea began in 1983 and is located on the East Rift Zone.
This photograph shows Kilauea Caldera and Halemaumau Crater. The East Rift Zone trends away from the caldera towards the top of the photo. A plume of gas can be seen rising above the Puu Oo cone.
Volcano Index
Explosions occurred over the last several weeks. Each of these explosions were followed by pyroclastic flows down all sides of the volcano.
Flows of pumice and ash reached the sea through the Tar River valley and White River valley. They also reached Farms, Dyer's and Plymouth.
The large amount of material deposited on the volcano during this activity allows each subsequent flow to travel farther.
Eruption columns rose
to heights of 20,000 to 40,000 ft (6000-12,000 m) after each explosion. Ash
and pumice clasts up to almost 1 inch (~2 cm) in diameter has fallen on inhabited
areas of Montserrat from these explosions.
Volcano Index
Popocatepetl is a snow capped stratovolcano that stands 13,776 ft (4200 m) above the surrounding basin.
The name Popocatepetl, meaning "Smoking Mountain", was given to the volcano by the Aztecs, and suggests that the volcano has long been active.
Popo, as it is often called, is built on an older volcano which adds 12,464 ft (3800 m) to Popocatepetl's elevation.
The new cone consists of many steep lava flows that alternate with thick pyroclastic layers.
Eruption Report:
Location : 19.02 N,
98.62 W
Summit height : 5,465 m
Volcanic Explositivity Index: 1-2
Popocatepetl, the second highest volcano in Mexico, is a giant stratovolcano, 70 km (~45 miles) southeast of downtown Mexico City, and 45 km (~30 miles) southwest of the city of Puebla.
Popo - as many people call it rather than struggling with its full name (Popo-cat-e-petal) - became active just before Christmas after five decades of quiet.
During the last two years the volcano has frequently had a small column of steam rising from its summit crater. After midnight on December 21, 1994 a series of earthquakes signaled that eruptions had started. That morning a gray ash cloud was visible over the top of the volcano, and ash fell on Puebla.
During the afternoon, the eruptions increased. Because most of the ash was blowing to the east, civil defense authorities decided to evacuate 19 villages (31,000 people) east of Popo.
Moderate eruptions have continued, and according to newspapers the total number of evacuees was about 75,000 people by December 26.
The United States Geologic Survey h