Updated 10/17/2009
A 7.9 Magnitude quake shook southern Sumatra on September 30, 2009 at 10:16 GMT, 5:16 PM local time. The epicenter was 31 miles west of the city of Padang, Sumatra, Indonesia. Padang is the capital of West Sumatra and has a population of 900,000. the quake was felt as far away as Singapore, 200 miles to the NE. 1,110 people have been reported dead, with 300 still unaccounted for. More than 2,000 are reported injured and over 100,000 building are reported destroyed, with another 100,000 damaged. Unoffical casualty reports have given a higher number of deaths, up to 4,000, but there is no indication how reliable that figure is. Early estimates of fatalities in Padang were reduced while the figures in outlying areas increased. Rescue efforts were hampered because many roads, bridges and telephone communications systems were damaged in the quake. Among the damaged buildings are schools, apartments, offices and hospitals. In places patients were treated in parking lots due to damage from the quake. Most of the casualties are the result of people caught in collapsing buildings.
While early rescue efforts concentrated on the city of Padang, outlying villages in the area were also badly damaged. Over 600 people are thought to be dead in this area. Many buildings in the Padang Pariman district were damaged when their metal roofs collapsed. The quake caused landslides that either undermined houses, sending them crashing down the hillside or buried them under tons of earth. A wedding celebration attended by 400 guests was buried by a massive landslide.
The international press gave this quake extensive coverage for a few days before moving on to other things, with few follow up stories.
The southern coast of Sumatra is prone to very large earthquakes. In this area, the Australian
Plate is subducting under the Sunda Plate to the northeast. As the plate is forced down under Sumatra into the Earth's mantle, it heats up releasing magma, which rises to form the island of Sumatra and the volcanoes which comprise it. There have been a series of megathrust quakes of over 8.0 M on different sections of the subduction zone. The 2004 tsunami was caused by a 9.0 megathrust quake at the northwestern end of Sumatra, about 500 miles from Padang. This earthquake was deeper, at 50 miles underground, than these quakes and the USGS says that it most likely occurred within the Australian plate below the plate boundary. At 7.6 M it was also not as strong than those others. This section of the fault has not had a large quake, over 8.0M, since 1797. The USGS says that it is not clear how this quake relates to the series of stronger, shallower quakes on sections of the fault zone on either side of this area. It is likely that this quake was not large enough to relieve the pressure that has been building up on this section of the subdection zone.
This quake is unrelated to the Somoan quake of the day before, which was centered 6,000 miles to the east in the Pacific Ocean.
A second large earthquake hit the following day 135 miles SE of Padang, closer to the city of Benkulu. This earthquake, with a Magnitude of 6.6, was strong enough to cause some damage, but there have been no reports of casualties. This quake was much shallower and was on the Sumatra fault in the overlying Sunda plate.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake.
See also the following news stories:
*Indonesia quake deaths pass 1,000 (BBC 10/1/09)
* In Pictures: Indonesian rescue effort (BBC 10/2/09)
*Huge aid push in Indonesia, quake levels villages (Reuters (10/2/09)
*Padang lives with quake stress (BBC 10/1/09)
*Village deaths to lift Indonesia death toll (AP 10/3/09)
*Sumatra quake 'levelled villages'(BBC 10/3/09)
*West Sumatra loses entire hamlets under landslides (The Jakarta Post 10/3/09)
*Indonesian quake toll soars to 1,115(Brisbane Times 10/13/09)
*Diggers to help rebuild quake-hit Padang(Brisbane Times 10/17/09)
*USU to send team to overcome quake victims` trauma(Antara News 10/17/09)
September 29, 2009 Somoa Quake and Tsunami
Updated 10/1/2009
The Samoa Islands were hit by a 7.9 M earthquake at 17:48 UTC (6:48 AM local time) on September 29, 2009. The epicenter was 139 miles SW of Pago Pago, American Somoa. The resulting tsunami caused considerable damage in both Somoa and in American Somoa. Over 150 people are estimated to have been killed as the coastal areas of all the Samoan islands were inundated. Casualties were reported from Somoa, American Somoa and Tonga. American Somoa is a US territory and has been declared a disaster area by President Obama.
Reports from the scene were that the quake was strong enough to rock buildings and cause rockslides in the mountains. It was distinguished more by its long duration of over a minute than by the strength of the shaking. This is indicative of a very strong quake that is distant enough to dilute its strength. Within 5 minutes the sea receded as the tsunami approached then swept ashore 10-15 feet deep. Boats were swept inland and cars were swept out to sea. Most people rushed to higher ground. A number of people were killed when they went down to the shore to gather stranded fish after the first wave receded, only to be caught by the second wave. Altogether there were 4 waves in the course of 20 minutes. There was extensive damage throughout the region. Although Somoa has a tsunami warning system, the tsunami hit too soon after the quake to allow the warning to take effect.
The earthquake occurred on the boundary between the Pacific and Australian Plates. The Pacific Plate subducts under the Australian Plate at the Tonga Trench. The epicenter was located near a bend in the plate boundary, at the northern end of the subduction zone. The magnitude has been reported as anywhere from 7.9 M to 8.3M. An earthquake of this size is catagorized as a "Great" earthquake and is capable of extensive damage. This is about the size of the 1906 earthquake that devastated San Francisco. In this case the fact that the quake occurred at sea over 100 miles from any populated area greatly reduced the damage from the quake itself. However, an earthquake of this size underwater does have the potential to create a tsunami, as this one did. The tsunami can travel great distances and in this case, the tsunami appears to have caused the most damage.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake.
See also the following news stories:
* Deadly Tsunami Strikes in Pacific (BBC 9/30/09)
*Somoa tsunami: survivors tell of giant walls of water (guardian.co.uk 10/1/09)
* Somoa tsunami lesson: Early warning system too slow (Christian Science Monitor 9/30/09)
The Samoa Islands were hit by a 7.9 M earthquake at 17:48 UTC (6:48 AM local time) on September 29, 2009. The epicenter was 139 miles SW of Pago Pago, American Somoa. The resulting tsunami caused considerable damage in both Somoa and in American Somoa. Over 150 people are estimated to have been killed as the coastal areas of all the Samoan islands were inundated. Casualties were reported from Somoa, American Somoa and Tonga. American Somoa is a US territory and has been declared a disaster area by President Obama.
Reports from the scene were that the quake was strong enough to rock buildings and cause rockslides in the mountains. It was distinguished more by its long duration of over a minute than by the strength of the shaking. This is indicative of a very strong quake that is distant enough to dilute its strength. Within 5 minutes the sea receded as the tsunami approached then swept ashore 10-15 feet deep. Boats were swept inland and cars were swept out to sea. Most people rushed to higher ground. A number of people were killed when they went down to the shore to gather stranded fish after the first wave receded, only to be caught by the second wave. Altogether there were 4 waves in the course of 20 minutes. There was extensive damage throughout the region. Although Somoa has a tsunami warning system, the tsunami hit too soon after the quake to allow the warning to take effect.
The earthquake occurred on the boundary between the Pacific and Australian Plates. The Pacific Plate subducts under the Australian Plate at the Tonga Trench. The epicenter was located near a bend in the plate boundary, at the northern end of the subduction zone. The magnitude has been reported as anywhere from 7.9 M to 8.3M. An earthquake of this size is catagorized as a "Great" earthquake and is capable of extensive damage. This is about the size of the 1906 earthquake that devastated San Francisco. In this case the fact that the quake occurred at sea over 100 miles from any populated area greatly reduced the damage from the quake itself. However, an earthquake of this size underwater does have the potential to create a tsunami, as this one did. The tsunami can travel great distances and in this case, the tsunami appears to have caused the most damage.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake.
See also the following news stories:
* Deadly Tsunami Strikes in Pacific (BBC 9/30/09)
*Somoa tsunami: survivors tell of giant walls of water (guardian.co.uk 10/1/09)
* Somoa tsunami lesson: Early warning system too slow (Christian Science Monitor 9/30/09)
April 6, 2009 L'Aquila, Italy Earthquake
Updated 4/7/2009
A 6.3 Magnitude earthquake hit L'Aquila, Italy, 55 miles north of Rome, at 01:32 GMT on April 6, 2009, 3:32 AM, local time, causing major damage and hundreds of deaths. Several aftershocks caused additional damage, including a 5.5 M quake on the 7th.
207 people have been confirmed dead, 1500 injured and over 17,000 homeless. L'Aquila is a city of 70,000. The original walled city was built in the 13th century. Although many older buildings collapsed, modern buildings were not spared. A hospital built as recently as 2000 partially collapsed, forcing patients out into the open and making it harder to treat them. Italy has building standards for earthquake resistant buildings but it is not always observed. Most of the casualties were caused by collapsed buildings as people slept. Heavy rains since the quake has hampered rescue efforts.
Survivors whose homes have been destroyed or are feared to be unsafe are sleeping in their cars, in hotels, or in tent cities that have been set up for the refugees. People have been digging in the rubble with their bare hands, as well as with heavier equipment. Some of the earliest stories were of people digging students out of a collapsed dormitory. Prime Minister Silvio Berlusconi pledged help in rebuilding the city.
Tectonically, Italy is in the center of a number of forces any one of which can cause quakes. Italy is involved in a collision to the north with Europe that is raising the Alps. At the same time a mini-plate to the east, the Adria (under the Adriatic Sea) is subducting beneath Italy, while the Tyrrhenian basin to the west (under the Tyrrhean Sea between the Italian mainland and the islands of Corsica and Sardinia) is expanding. This quake, in the middle of Italy in the Apennine mountains is related mostly Tyrrhean expansion. This area has been the site of major earthquakes in the past. In 1997 a series of earthquakes killed 11 people and caused significant damage. In 1703 a large earthquake destroyed much of the city.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake.
See also the following news stories:
* Strong Quake in Italy kills over 150, wounds 1500 (AP 4/6/09)
* Aftershocks hit Italy quake zone (BBC 4/7/09)
* Italy Earthquake deaths soar(BBC 4/7/09)
* Quake buildings 'below standard'(BBC 4/7/09)
* Did a Seismologist Accurately Forecast the L'Aquila Earthquake--Or Was It a Lucky Guess?(Scientific American 4/7/09)
A 6.3 Magnitude earthquake hit L'Aquila, Italy, 55 miles north of Rome, at 01:32 GMT on April 6, 2009, 3:32 AM, local time, causing major damage and hundreds of deaths. Several aftershocks caused additional damage, including a 5.5 M quake on the 7th.
207 people have been confirmed dead, 1500 injured and over 17,000 homeless. L'Aquila is a city of 70,000. The original walled city was built in the 13th century. Although many older buildings collapsed, modern buildings were not spared. A hospital built as recently as 2000 partially collapsed, forcing patients out into the open and making it harder to treat them. Italy has building standards for earthquake resistant buildings but it is not always observed. Most of the casualties were caused by collapsed buildings as people slept. Heavy rains since the quake has hampered rescue efforts.
Survivors whose homes have been destroyed or are feared to be unsafe are sleeping in their cars, in hotels, or in tent cities that have been set up for the refugees. People have been digging in the rubble with their bare hands, as well as with heavier equipment. Some of the earliest stories were of people digging students out of a collapsed dormitory. Prime Minister Silvio Berlusconi pledged help in rebuilding the city.
Tectonically, Italy is in the center of a number of forces any one of which can cause quakes. Italy is involved in a collision to the north with Europe that is raising the Alps. At the same time a mini-plate to the east, the Adria (under the Adriatic Sea) is subducting beneath Italy, while the Tyrrhenian basin to the west (under the Tyrrhean Sea between the Italian mainland and the islands of Corsica and Sardinia) is expanding. This quake, in the middle of Italy in the Apennine mountains is related mostly Tyrrhean expansion. This area has been the site of major earthquakes in the past. In 1997 a series of earthquakes killed 11 people and caused significant damage. In 1703 a large earthquake destroyed much of the city.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake.
See also the following news stories:
* Strong Quake in Italy kills over 150, wounds 1500 (AP 4/6/09)
* Aftershocks hit Italy quake zone (BBC 4/7/09)
* Italy Earthquake deaths soar(BBC 4/7/09)
* Quake buildings 'below standard'(BBC 4/7/09)
* Did a Seismologist Accurately Forecast the L'Aquila Earthquake--Or Was It a Lucky Guess?(Scientific American 4/7/09)
10/29/2008 Pakistan Earthquake
Updated 10/30/2008
A 6.4 Magnitude earthquake hit near Ziarat, Pakistan at 23:10 GMT on September 28, 2008. 4:10 AM, September 29, local time. A 2nd quake, almost as strong followed about an hour later, and there have been several strong aftershocks. The epicenter was 400 Miles West of Islamabad, 35 miles NW of Quetta and 115 miles SE of Kandahar. Quetta, the capital of Balochistan, is a city with a population of 535,000 in western Pakistan, near the border with Afghanistan. There are also an estimated million Afghan refugees in the area.
The death toll is at 215, with up to 50,000 homeless. The government is using helicopters to reach the affected areas. Some villages were cut off by landslides and many houses have been destroyed. The quake occured in the predawn hours and victims were buried as they slept. There is a great need for shelter and supplies. People have been sitting outside and are hungry and cold. The Red Cross distributed 2,300 tents with many more needed. India, the US and the UN have all pledged aid. Help is also being provided by Islamic organizations in the area, including Jamat-ud-Dawa, which also helped in the aftermath of the Kashmir quake in 2005.
The quake is caused, in the broad scheme of things by the collision, on a continental scale, of India and Asia. India was a separate land mass that has during the last few million years, moved across the Indian Ocean and is currently slamming into southern Asia. The energy from that collision raised the Himalayas and radiates out from there, causing often destructive earthquakes. In 1935 an earthquake in the same general area killed 30.000 people.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes. See the USGS summary of this quake .
See also the following news stories:
10/5/08 Kyrgystan Earthquake
The 6.6 Magnitude quake occurred at Sunday, October 05, 2008 at 15:52:49 UTC (9:52 PM local time)near the village of Nura, about 275 miles east of Dushanbe, Tajikistan, on the border with China. It was felt throughout the Central Asian region. 74 people were killed, 120 injured and dozens of buildings destroyed,, much of in Nura. The damage occurred on both sides of the Chinese-Kyrgystan border.
Geologically, the quake was caused by stresses in the Asian landmass resulting from the collision of India into Eurasia. India is actually a separate tectonic plate, whose head-on collision with Asia has raised the Himalayas and caused many destructive earthquakes. Although the collision is hundreds of miles south of this earthquake the crust is being deformed over a very large area, causing many earthquakes, including this year's China and Pakistan quakes. This is an unusual plate boundary in that two continental plates are hitting head-on. In other areas, one plate may be pushed under another, where they cause large subduction quakes, like the 2004 Sumatra quake that caused the destructive tsunami. Another possibility is that two plate may move sideways past each other, as happens at the San Andreas fault, causing quakes like the 1906 San Francisco quake
Geologically, the quake was caused by stresses in the Asian landmass resulting from the collision of India into Eurasia. India is actually a separate tectonic plate, whose head-on collision with Asia has raised the Himalayas and caused many destructive earthquakes. Although the collision is hundreds of miles south of this earthquake the crust is being deformed over a very large area, causing many earthquakes, including this year's China and Pakistan quakes. This is an unusual plate boundary in that two continental plates are hitting head-on. In other areas, one plate may be pushed under another, where they cause large subduction quakes, like the 2004 Sumatra quake that caused the destructive tsunami. Another possibility is that two plate may move sideways past each other, as happens at the San Andreas fault, causing quakes like the 1906 San Francisco quake
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes.
See the USGS summary of this quake .
See also the following news stories:
5/12/2008 China Earthquake
Updated 1/3/09
A 7.8 Magnitude earthquake hit Eastern Sichuan province in China at 06:28 GMT on May 12, 2008. 2:28 PM local time. The epicenter was 960 Miles SW of Bejing, 50 miles West of Chengdu, a city of 4 million. The nearest city is Dujiangyan, with 600,000 population, which is about 45 miles from the epicenter. Dujiangyan suffered major damage and at first is the center of the rescue efforts. 88,000 people died in the quake, including as many as 10,000 children killed when their schools collapsed. More than 5 million buildings are estimated to have collapsed.
Rescue teams had difficulty just reaching the epicenter in Wenchuan county. Landslides blocked the roads past Dujaingyan making access difficult. Fortunately the road from Dujiangyan to Chengdu was kept open for rescue vehicles. The quake was felt over a very wide area of China, as far away as Bejing.
During the first few days after the quake there were frequent aftershocks, including at least 6 over 5.5 Magnitude, strong enough to cause additional damage. Residents were afraid to go back inside, but the heavy rain made it difficult to stay outside. Government issued tents and tarps are helping a bit but many people spent days outside in the wet and cold. There are fears of illness developing from these conditions, especially among the old and young. Schools and hospitals were among the buildings destroyed, making it difficult to administer medical aid to survivors. Some schools collapsed while classes were in session, trapping students. The army has taken charge of the rescue efforts, with over 50,000 troops being deployed to the region. Heavy earthmoving equipment is being brought into the area and rescue teams are going to work in as organized a fashion as possible, Given the chaotic conditions. Traffic into the worst hit area is restricted to rescue efforts. Many residents have left the area and gone to Chengdu for shelter and services.
Another concern has been damage to dams. Soldiers were set to work trying to mend cracks to shore them up. 34 new lakes have also been formed as the result of landslides blocking rivers. These new lakes are even more unstable and there was some concern over the possibility that a dam could break in the continuing heavy rains, adding floods to the disaster. Luckily this did not happen.
The Chinese government has pledged $10 billion for earthquake relief. International aid is also flowing into the area. However the government warns that more is needed, especially tents, blankets, clothes, food and medical supplies. They estimate that 3.3 million tents are needed. 10 days after the quake 400,000 tents arrived in the region. 7 months later many are still living in temporary housing provided by the government. A group of parents are suing over alleged shoddy construction practices that they say contributed to the collapse of so many schools. This suit is the subject of a film, "Who Killed Our Children?" by Pan Jianlin, which was shown at the Pusan International Film Festival in South Korea. The government offered compensation to parents who agreed to drop their demands for an investigation of school construction.
The quake is caused, in the broad scheme of things by the collision, on a continental scale, of India and Asia. India was a separate land mass that has during the last few million years, moved across the Indian Ocean and is currently slamming into southern Asia. The energy from that collision raised the Himalayas and radiates out from there, causing often destructive earthquakes. In 1933 an earthquake in the same general area killed 9300 people.
(See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes.
US Geological Survey page on this earthquake
See also the following news stories:
- Winter and economy chilling China quake zone (Reuters 12/8/08)
- Dam may have caused deadly China earthquake(USA Today 1/29/09)
- UN head visits China quake zone (BBC 5/24/08)
- China reiterates urgent need for tents in quake-hit areas (Xinhua 5/22/08)
- Rescuers reach Chinese epicentre (BBC 5/13/08)
- Chaotic yet organised rescue effort(BBC 5/13/08)
- Chengdu witness: Fear of going home(BBC 5/13/08)
- In pictures: China's ruined valley(BBC 5/20/08)
- Parents of Schoolchildren Killed in China Quake Confirm Lawsuit (NY Times 12/22/08)
- China earthquake in video
7/16/2007 Honshu, Japan
Updated 9/22/2007
This 6.6 Magnitude quake hit at 10:13 AM local time (01:13 GMT), just off the west coast of the island of Honshu in central Japan. The epicenter was 45 miles west of the city of Nigata and 150 miles to the northwest of Tokyo. It was followed a couple of hours later by a 6.8 M quake nearby. Although the second quake was stronger, it was focused depper and thus cause less damage. According to the US Geological Service account of the quake, these quakes were different enough that the second one is not considered an aftershock of the first.
The earthquake caused damage to 875 buildings, especially older ones, 1,088 injuries and 11 deaths. The shaking was so strong that people said they couldn't stand during the quake. A nuclear power plant remains shut down two months after the quake due to damage that resulted in the release of radiation. This accident follows several other incidents at nuclear power plants in Japan that have called into question the safety of Japan's extensive nuclear power program.
Japan is located at the western edge of the Pacific Plate, where it interacts with the Eurasian Plate and some small tectonic plates inbetween. This results in many earthquakes as these plates interact. In 2004 a 6.6 M quake in the same general area killed 40 people and injured 3,000. The US Geological Service account of the quake describes the geology in more detail. (See the Plate Tectonics page for more information on these processes.) The US Geological Survey (USGS) is an invaluable resource in understanding and tracking earthquakes.
See also the following news stories:
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