5/21/2003 Algeria Earthquake

Updated 5/24/2003

The 6.7 Magniture earthquake struck at 18:44 GMT 5/21/03. This was 7:44 pm local time. The epicenter was in Bourmedes, 45 miles east of Algiers in Northern Algeria. Scores of buildings collapsed in the first seconds of the quake. Over 1,875 have died, over 1.000 in Bourmedes and over 7,000 injured. Thousands more camp out in the streets because their homes have been destroyed or out of fear of aftershocks. Accoridng to the BBC, "In Reghaia, 35km (22 miles) east of Algiers, authorities requisitioned the municipal stadium, setting up tents for families whose houses were destroyed in the earthquake. " There have indeed been many strong aftershocks. Rescuers have been desperately digging in the rubble with bulldozers and their bare hands desperately trying to find people who are still alive. After the first two days there is little hope of finding more survivors. Hospitals are totally overwhelmed with thousands of people coming in with serious injuries. Communications are difficult with phone lines down. Many roads have been damaged, huge traffic jams make access to the area difficult. Remote villages are especially cut off with roads cracked and blocked with debris. Large crowds of relatives are pouring into the area, adding to the congestion. Medical supplies are in short supply.

Algeria has requested international aid to cope with the massive damage. France has sent aid, including rescue equipment and rescue dogs. The dogs have been trained to find people under debris. Other countries are also contributing. French President, Jacques Chirac stressed historic ties between France, the former colonial power, and Algeria, in sending aid. UNICEF, the Red Cross and Red Crescent Societies and others are contributing to the effort.

Two days after the quake, crowds turned their grief and anger towards the Algerian President when he toured the disaster area. Boos and stone throwing were reported. Local Newspapers also attack the lack of preparations and response to a quake in this very seismically active region. They accuse the government of an inadequate response and of allowing substandard construction of the buildings that collapsed. The government has been accused of slow response and poor co-ordination of the rescue efforts. Foreign aid workers are finding that government security concerns are also slowing them down. They are experiencing tight checks at the border. Conflicts between government security forces and Islamic militants complicate the issue. Road crews are working with armed escorts and the government is reluctant to send rescuers into areas where they might be caught up in the conflict.

This quake was casued by the collision between the African Tectonic Plate, which is moving northward into Europe. The Northern Algerian area has been hit repeatedly by severe quakes. The USGS describes this process as follows: "The earthquake occurred in the boundary region between the Eurasian plate and the African plate. Along this section of the plate boundary, the African plate is moving northwestward against the Eurasian plate with a velocity of about 6 mm per year. The relative plate motions create a compressional tectonic environment, in which earthquakes occur by thrust-faulting and strike-slip faulting. Analysis of seismic waves generated by this earthquake shows that it occurred as the result of thrust-faulting. Algeria has experienced many destructive earthquakes. On October 10, 1980, the city of El Asnam (formerly Orleansville and today Ech-Cheliff) was severely damaged by a magnitude 7.1 earthquake that killed at least 5000 people. The site of El Asnam is situated approximately 220 km to the west of the recent earthquake. The same city, as Orleansville, had been heavily damaged on September 9, 1954, by a magnitude 6.7 earthquake that killed over 1000 people. On October 29, 1989, a magnitude 5.9 earthquake struck about 110 km to the west of the recent earthquake and killed at least 30 people."

(See the Plate Tectonics page for more information on these processes.)

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2/24/2003 China Earthquake

Updated 2/27/2003

The earthquake was given a magnitude of 6.4 by the US Geological Survey. It struck at 02:03 GMT Monday morning. This was 10:03 local time but because the area is in the extreme west of China's one time zone, it was shortly after dawn and many people were at breakfast. Others had just started school or work. The epicenter was in Xinjiang province 65 miles from the city of Kashi. This is in the extreme west of China, 2070 miles west of Beijing. It is generally poor, sparsely populated region, inhabited by Uighurs, a Muslim people, related to those in Kyrgyzstan and other Central Asian countries nearby.

The death toll was confirmed at 266, following strong aftershocks on 2/25/03 that killed 5 more people, including some rescue workers. Estimates of injuries range from 1,000 to 4,000. Over 9,000 buildings were destroyed. Most casualties were caused when people were trapped in their collapsing houses. CNN reported: "Almost all the dead were in Bachu County, where flimsy building construction seemed to have contributed to the death toll, officials said. The neighboring county of Jiashi was closer to the epicenter but suffered little damage; its homes have been reinforced following severe quakes in recent years."

The BBC reported: "The quake had a severe effect on the local economy, which is heavily dependent on farming. Some 11,000 cattle were killed and at just one farm in Qiongkuerqiake, 190 sheep were crushed. Local residents cannot eat them because they have not been butchered according to Muslim tradition. "

The army immediately sent in rescue crews to help dig survivors out of the rubble. Dogs are also being used to locate survivors. The Chinese government is providing aid but has not issued an international appeal.

This quake was casued by the collision between the Indian Sub-continent, which is plowing northward into Asia. This collision raised the Himalayan Range and causes earthquakes throughout the whole Central Asian region. The USGS describes this process as follows:

"This earthquake occurred near the boundary between the Tarim Basin and the Tian Shan mountain range in the north-west Tarim Basin. In a broad sense, earthquakes in this region result from stresses induced by the collision of the Indian and Eurasian continental plates, even though the boundary between these plates lies about 1000 km to the south.

The Indian Plate continuously moves northward at a rate of 4.5 cm per year relative to the Eurasian Plate generating massive mountain ranges including the Himalaya and causing the uplift of the Tibetan Plateau. These stresses are transmitted to the north, through the rigid and undeforming Tarim Basin, where they generate the Tian Shan mountains and numerous earthquakes like this recent event. Several nearby mapped faults have orientations similar to the thrust fault that the earthquake occurred on, although seismologists have not yet associated the quake with a specific fault.

The region surrounding this earthquake has produced several deadly earthquakes in the past decade. The most destructive include a magnitude 6.3 event on March 19, 1996, a magnitude 5.9 on January 21, and a magnitude 6.2 on April 11, 1997. Each quake killed between 10 and 24 people, and destroyed thousands of buildings. The most recent significant earthquake occurred on August 27, 1998 killing 2 and destroying 3,600 homes. " (See the Plate Tectonics page for more information on these processes.)

USGS Bulletin for the 2/24/03 China quake

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6/22/2002 Iran Earthquake

Updated 6/30/2002

On Saturday June 22, 2002 at 7:28 AM local time (02:58 GMT) a magniture 6.5 earthquake hit northwest Iran. It was centered around the town of Bou'in-Zahra, in northern Qazvin province about 240 miles west of Teheran. The death toll was originally thought to be over 500 but within a few days was revised downwards to 245. There were an estimated 1,500 injuries and 5,000 homes were destroyed leaving 25,000 people homeless. Nearly 100 villages were badly damaged or destoyed, according to the Red Crescent. Most of the dead were buried when their unreinforced homes collapsed. Emergency services were strained, with local people complaining that the government was too slow to get help to the region and that the death toll was actually higher than the official reports. Efforts to prevent the spread of disease include spraying disinfectant.

International aid has been offered by many countries, including the US, in spite of the strained relations between the two countries. Iran has declared that it will accept some US humanitarian aid.

There have been many strong aftershocks, up to 5.1 Magnitude.

This quake was casued by the movement of the Arabian Plate as it moves to the northwest relative to the Eurasian Plate. The quake had a shallow focus as the earth's crust adjusted to the strain caused by this collision. Frequent shallow focus quakes are the rule in this area. The USGS describes this process as follows: " This recent Iranian earthquake occurred in the Zagros fold-and-thrust belt. This highly seismic region forms the boundary between the Arabian and Eurasian plates. The Arabian Plate is a small plate split from the African Plate by rifting along the Red Sea. As it collides with the massive Eurasian Plate it causes uplift of the Zagros mountains and numerous damaging earthquakes. " (See the Plate Tectonics page for more information on these processes.)

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3/25/2002 Afghan Earthquake

Updated 3/28/2002

On the morning of March 25, 2002 at 6:18 GMT GMT a 6.1 magnitude earthquake was felt in Northern Afghanistan. Initial reports set the death toll at 1,800 but that has been revised downwards to about 1,000. The shallow focus of the quake led to more severe shaking at the surface and thus more damage than a deeper quake of the same magnitude. Buildings are not built to resist quakes, using stone and masonry, which are easily damaged by the frequent earthquakes. The area hit has suffered from drought, famine and war in the last few years. Whole villages are reported to have been leveled with thousands homeless. The initial quake has been followed by a series of severe aftershocks and related quakes that compounded the damage. The same general area has been hit by major earthquakes on a regular basis.

Aid was immediately rushed to the area. Roads to the affected areas are difficult under the best of circumstances and made worse by earthquake caused landslides. Aid has gotten through by helicopter, with the international peacekeeping force in Kabul helping out. Many aid workers are already in the country helping victims of famine and war. Relief efforts may be hampered by landmines and the fear of Al Quaeda attacks. A statement apparently from Al Quaeda blames the quake on God's Punishment for the war against the Taliban. This quake was casued by the movement of the Indian Plate as it moves northward into the Eurasian Plate. The quake had a shallow focus as the earth's crust adjusted to the strain caused by this collision. (See the Plate Tectonics page for more information on these processes.)

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2/3/2002 Turkish Earthquake

Updated 2/3/2002

On the morning of February 3, 2002 at 7:11 GMT (09:11 local time) a 6.2 magnitude earthquake was felt in Western Turkey. The epicenter was 130 miles SW of Ankara, 300 miles SE of Istanbul. 45 people have been confirmed dead with at least 130 injuries.

Afyon province at the epicenter is a sparsely populated rural area. Most casualties were in industrial developments, where several buildings collapsed. Since the quake occurred on Sunday morning when most people were home, there are fewer casualties than there might have been had the quake been at a different time. The Turkish government immediately sent 3000 tents and rescue workers. President Echivit visited the area. The government had been criticized for its slow response to the much larger 1999 quake. This was a shallow quake, only 10 km deep. In general quakes at this depth are caused by lateral movements of the earth's crust. The quake occurred in an area characterized by frequent shallow quakes. The entire west coast of Turkey from the Black Sea right around the coast down to the Mediterranean is part of this zone. Istanbul is the largest city in this area and is definitely considered at risk for a major quake with thousand of casualties. This part of Turkey is located near the intersection of three major tectonic plates. The Eurasian Plate is to the north, The African and Arabian plates to the South and Southeast are moving generally northwards, squeezing Turkey in the process. Earthquakes on the Anatolian Fault are the result of these pressures. (See the http://theearthquakemuseum.weebly.com/plate-tectonics.html">Plate Tectonics page for more information on these processes.)

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6/23/2001 Peru Earthquake

Updated 7/2/2001

On the afternoon of June 23, 2001 at 20:33 GMT (15:33 local time) a 8.1 magnitude earthquake struck southern Peru. The epicenter was 110 miles (180 km) SSE of Puquio, Peru,120 miles (190 km) W of Arequipa, Peru , 200 miles (325 km) SSW of Cuzco, Peru and, 375 miles (600 km) SE of LIMA, Peru. 102 people have been confirmed dead with 1,368 injuries and 46,470 estimated homeless according to Peru's Civil Defense Institute. The biggest city in the area is Arequipa, Peru's second largest. Other cities that were hard hit include Moquegua and Tacna. Portions of Bolivia and Chile also were affected with relief efforts also ongoing there. Communications following the quake have been hampered by damaged roads, mudslides and downed electric and phone lines.

Arequipa is known for beautiful colonial architecture. Many of these buildings have been severely damaged, including the cathedral, which was originally built in 1656. One of its steeples fell and the other was severely damaged. Traffic has been restricted in the central section of the city because of fears that the vibrations could cause further collapse.

Witnesses said that the ground made huge waves during the quake, which lasted over 1 minute. A tsunami caused by the quake drowned 39 people in a coastal village but tsunami warnings for the Pacific were withdrawn with no damage elsewhere.

Earthquakes over 8 Magnitude are known as "Great" Earthquakes and are capable of largescale devastation. This quake would have been much more damaging in a more heavily populated area.

The Earthquake occurred in the Nazca Tectonic Plate just off the coast. The Naca Plate and the South American Plate are moving towards eachother. At this point the Nazca Plate is just starting to descend under the South American Plate. This quake was considered shallow, only being about 20 mi (33 km) deep. As the Nazca Plate moves east it descends deeper and deeper until it hits the earth's mantle, where the heat and pressure are enough to melt and absorb it. Magma rises from this point to fuel the Andes' volcanoes. As you move east from the coast, earthquakes originate deeper and deeper in the descending plate. (See the Plate Tectonics page for more information on these processes.)

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2/28/2001 Nisqually, Washington Earthquake

Updated 3/2/2001

The quake occurred at 18:55 GMT (10:55 AM Pacific Standard Time). The magnitude was 6.8. The epicenter was between Tacoma and Olympia, Washington, about 10 miles northeast of Olympia. The focus of the quake was 30 miles deep. It was felt strongly in Portland and Vancouver, British Columbia. There were also reports that it was felt in San Francisco and Salt Lake City.

320 people were injured, 4 seriously. Damage estimates are over $2 billion. There have been considerably reports of damage, especially in Olympia near the epicenter of the quake. There have been many buildings there suffering structural damage. There is a large crack in the dome of the State Capitol Building and serious damage to other state office buildings. The legislature is right in the middle of its 105 day session. Both the Governor, the legislature and the state Supreme Court have had to relocate due to serious damage to their buildings. The Governor's Mansion is uninhabitable. Governor Locke's 2 year old son just missed being hit by a television that fell over in the Governor's Mansion. Some streets and sidewalks were badly buckled. There were also cracks in the ground up to several inches wide. Seattle skyscrapers swayed violently but apparently not dangerously. Lots of windows were broken and many buildings in downtown Seattle suffered a lot of damage, especially in the historic Pioneer Square district. In many places bricks fell from building facades. Some parked cars were covered with debris. Harborview Medical Center in Seattle closed one wing and evacuated patients. About 30 people were stranded for a couple of hours in the Space Needle while the elevators were checked. Some buildings were evacuated and Sea-Tac airport was closed for 4 or 5 hours. There was considerable damage to the Control Tower, with many of the windows broken. The Air Traffic controllers were temporarily relocated to vans next to the runway. The Portland airport was also closed. Seattle Ferry traffic was disrupted while the Seattle dock was evaluated. Passengers were stranded for a few hours on ferries that happened to be on the water at the time. Some highway bridges, including the Alaskan Way Viaduct, an elevated freeway along Seattle's waterfront were closed while crews checked for damage. Landslides closed some highways in the Cascades as well as Highway 101 north of Olympia. 100,000 people lost power but most of it was restored by the end of the day. Most of the damage was in the Olympia and Seattle areas, although there was isolated damage further away. The Peninsula College Little Theater in Port Angeles was closed due to damage and one historic office building in downtown Port Townsend had several cracks in its facade. A middle school gym in Port Townsend may also have suffered structural damage.

School children throughout the area followed instructions from their earthquake drills and ducked under their desks when their teachers told them, "We are having an earthquake. Duck under your desks and stay quiet so we can hear." Most schools were undamaged and the school day continued. Some parents did pick up their children early though.

Immediately after the quake there were large crowds of people milling around in the streets of Seattle, Olympia and as far away as Portland. Many people were alarmed by the buildings swaying in the quake and ran out into the street. In general, downtown streets are the least safe place to be during and immediately after an earthquake. The most common damage is broken windows and collapse of building facades. Both of these will shower the streets below with debris. Even when buildings do collapse they often fall into the streets. (In the Indian earthquake in January 350 schoolchildren were buried under a collapsed building facade as they marched down the street in a parade.) If there had been aftershocks to this quake, it could have brought down more debris onto the crowds below. The congestion may also have interfered a bit with emergency response. Many people were sent home early leading to considerable traffic congestion throughout the day.

This quake was similar to the quakes in Seattle in 1939 and on 4/13/1949 and 4/29/1965. The 1949 7.1 quake released 3 times as much energy as this quake. The relatively deep focus of the earthquake tended to lessen the damage since it put the focus further from the surface. The relatively deep focus also spread out the effects over a large area. The quake was caused by tensional faulting in the Juan de Fuca plate, which is subducting under the North American Plate in this area. The plate is under strain as it is bent while going under the North American Plate.

The Seattle fault is a shallower fault in the North American Plate that is also thought to be a danger for an earthquake that could cause considerably more damage. The prospects for an earthquake on the Seattle fault are not thought to be affected by this quake. The prospects for a major subduction quake off the Pacific Coast are probably not affected either. A major subduction quake could have a magnitude of 8-9 causing major damage over a large area as well as a possible tsunami. (See the Plate Tectonics page for more information on these processes.)

This quake was rated as moderate. There are several quakes this large every year throughout the world. Damage from a quake of this size depends largely on how near it is to population centers and the types of buildings in the area. In an area with unreinforced masonry buildings and no building codes, a quake like this could cause hundreds, even thousands of casualties. In a relatively unpopulated area, it could cause very little damage. This quake was in a major urban area, so it affected a lot of people, but an area that was aware of earthquake risks and has had building codes in place that require quake safe building methods. Many, but not all, older buildings have been retrofitted to improve their resistance to earthquakes. This quake can also be contrasted to the 1994 Northridge earthquake, which had a 6.7 magnitude, similar to this one, but with a shallower 11 mile deep focus, That quake caused a lot more damage and killed 72 people.

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