Wednesday, September 30, 2009

Indonesia Earthquake (magnitude 7.6) - John Seach

A magnitude 7.6 earthquake hit 30 km offshore from Padang, Sumatra, Indonesia today (30th September 2009) at 5:16 pm local time. Active volcanoes close to the earthquake epicentre include Talang, Tandikat, Marapi, Kerinci, and Sorik Marapi. Talang volcano erupted after the Great 2004 earthquake. A significant tsunami was not generated with a wave height of 0.27 m measured at Padang.
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Samoa Earthquake (Magnitude 8) and Tsunami - John Seach

A magnitude 8.0 earthquake hit Samoa Tuesday 29th September 2009 at 6:48 am local time. The shallow earthquake generated a tsunami which hit Samoa causing destruction to villages and causing an unknown number of deaths. Tsunami height was 1.5 m at Pago Pago (Samoa), 0.7 m at Apia Upolu (Samoa) and 0.4 m at Rarotonga (Cook Islands). A wider tsunami watch for the Pacific Ocean was later cancelled. The closest volcano to the earthquake epicentre is Curacoa is Tonga, 170 km west. Curacoa volcano last erupted in 1979.
Volcanoes of Samoa...
Volcanoes of Tonga...

Monday, September 28, 2009

Dieng Volcano, Indonesia - John Seach

A phreatic explosion occurred at Sileri crater, Dieng volcano, Indonesia on evening 26-27 September 2009. The eruption lasted for 15 seconds. Between 1-19 September there were 2 volcanic earthquakes, 20-23 September 1 volcanic earthquake, 24th September 1 volcanic earthquake, no volcanic earthquakes on 25-26 September. The explosion was heard at a distance of 2 km from the crater. During the phreatic eruption, mud was ejected to a radius of 140 m. Temperature of water in Kawah Sileri remained fairly constant at about 70 deg C. There was no emissions of toxic gas at the eruption site and surroundings. The alert level at the volcano remains at "Normal". No evacuations were ordered. People are advised to stay at least 500 m away from the craters Sileri, Sinila, Timbang, Siglagah, and Sikidang. The last eruption at Dieng volcano occurred at Kawah Sibanteng on 15th January 2009.
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Sunday, September 27, 2009

Kilauea Volcano, Hawaii - John Seach

Seismic tremor remains elevated, and is increasing at Kilauea volcano in Hawaii. Over the past day, four earthquakes have been recorded beneath the volcano - three in the summit area, and one beneath the south flank. Three deflation-inflation events have occurred at Kilauea this week. This is caused by changes in a secondary magma chamber east of Halemaumau Crater at about 750 m below ground level. This secondary magma chamber produces episodic deformation events such as occurred this week. Deflation-inflation events typically have the following features - in the first phase, tiltmeters surrounding Kilauea caldera record slow deflation centered at the Halemaumau magma chamber that persists for about 24 hours. The second phase begins as the slow deflation abruptly gives way to rapid inflation, which is centred at Halemaumau magma chamber. The inflation phase is short-lived, lasting about 20 minutes. In the final phase, tiltmeters record exponentially decaying deflation, lasting from 8 to 20 hours, which returns the final tilt close to pre-event levels. The seismicity during deflation-inflation events is dominated by bursts of volcanic tremor at the onset of the inflationary phase. Along the east rift zone, lava continues to flow through tubes to the coast and is entering the ocean at Waikupanaha.
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Saturday, September 19, 2009

Soufriere Hills Volcano, Montserrat - John Seach

Soufriere Hills volcano on Montserrat has been relatively quiet for six months. There has been no extrusion of new lava, and no explosions in that period. Surface activity was restricted to rockfalls and occasional small pyroclastic flows from the dome, together with mudflows. While gas emission has remained unchanged, the number of earthquakes recorded has fallen to the lowest level seen during the eruption cycle. This suggests the long-term activity has changed at the volcano. It could possibly mean the "beginning of the end" of the eruption cycle. Formal end of eruption criteria have not yet been met. However, the risks to people living near the volcano have not changed, and sudden resumption of explosive and extrusive activity can rapidly pose a threat to adjacent areas.
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Wednesday, September 16, 2009

Alamagan Volcano, Mariana Islands - John Seach

Super typhoon Choi-Wan passed directly over Almagan island at 4pm on 15th September 2009. Maximum wind speeds reached 150 miles per hour. There were 15 people living on the island, but no injuries or damage was reported.
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Tuesday, September 15, 2009

Mayon Volcano, Philippines - John Seach

Three minor ash explosions occurred at the summit crater of Mayon Volcano in Philippines today at 5:37 am. The eruptions lasted for 3 minutes and produced a brown ash column which rose 700 m above the summit. Eleven volcanic earthquakes were recorded in the past 24 hours. Mayon volcano remains at level 2 alert. A 6 km radius Permanent Danger Zone, and 7 km Extended Danger Zone on the southeast flank of the volcano remain in place.
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Thursday, September 03, 2009

Kanlaon Volcano, Philippines - John Seach

There has been a large increase in volcanic earthquakes at Kanlaon volcano, Philippines. Between 23rd August and 1st September there were 257 earthquakes measured. This seismic activity is higher than the background levels, which usually varies from 0 to 4 events in 24 hour period. Two earthquakes were felt by residents surrounding the volcano. At 5:26 PM on August 23, 2009 one earthquake was felt at Intensity II in Barangay Ara-al, La Carlota City. A second earthquake at 10:27 PM on August 30, 2009 was felt at Intensity III in La Castellana and Intensity IV in La Carlotta City and Bago City. Epicenters of the earthquakes clustered at the north-west slope of the volcano. These earthquakes may indicate movements of an active local fault which may be caused by magma movement beneath the volcano. Surface observations did not indicate significant change in the steam emission from the crater. Since Kanlaon Volcano has a history of sudden steam-driven explosions without precursors, the public is reminded to avoid entering the 4 km Permanent Danger Zone. The status of Kanlaon Volcano is maintained at Alert Level 0.
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Wednesday, September 02, 2009

Indonesia Earthquake (Mag 7.0) - John Seach

A magnitude 7.0 earthquake hit 180 km SSE of Jakarta, Indonesia today 2nd Sept 2:55 pm local time. A tsunami watch was later cancelled. Volcanoes within 100 km of the epicentre include Galunggung, Guntur, Papandayan, Patuha, and Talagabodas.
Volcanoes of Indonesia...