Seismo-Watch

More Special Earthquake Reports

January 22, 2003

An earthquake measuring M 7.8 (NEIC) occurred today at 02:06:35 GMT along the coast of Central Mexico near Colima. Reports indicate the quake shook the region hard, causing significant damage, killing at least 29 people and injuring hundreds. Rescue operations are focused on locating survivors in the many damaged buildings and in outlying communities.

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According to the US Geological Survey's National Earthquake Information Center (NEIC), the earthquake struck at 8:06 p.m. Tuesday evening (local time), January 21 (02:06:35 GMT, January 22) about 300 miles northwest of Mexico City, 86 miles southwest of Guadalajara, 32 miles south-southwest of Colima, and 8 miles south of Tecoman, in a remote area on the coast. See maps.

The focal point was at 24 km beneath the surface and the NEIC fault plane solution suggested thrust motion (up and over) along a northwest trending plane. Although the epicenter is on land, the projection of the fault plane towards the surface suggests that if surface fault ruptures had occurred, they probably would be off shore in the Pacific Ocean.

Preliminary reports indicate a tsunami was recorded at Manzanillo, where a tidal gauge posted a peak to trough 1.22 meter tidal surge, followed by a prolonged sitch period. See news brief and chart.

There have been no reports of coastal elevation changes at this time.

The quake was centered along the very seismically active Central America subduction zone, a convergent tectonic boundary between the North America and Cocos plates. Slightly to the northwest is a small microplate, the Rivera plate, and a few tens of miles off shore is the East Pacific Rise, the spreading center between the Cocos and Pacific plates, adding to the complex tectonic environment of the region.

Earthquakes are common along the Central Mexican coast. This recent event occurred close to a devastating M 7.9 temblor in 1995 that killed 49 people and nearly destroyed the coastal resort town of Manzanillo. See list of M 7.3 earthquakes since 1973.

Damage Reports

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Preliminary reports indicate significant damage has occurred, killing more than 29 people and injuring hundreds. A state of emergency has been declared in several towns. The temblor was felt strongly as far away as Mexico City where tall buildings swayed and people ran into the streets.

The hardest-hit area is the state of Colima, where many homes and walls simply crumbled because of the intense seismic waves. The Jalisco and Michoacan states also suffered damages. Damage photos.

Rescuers are searching through rubble for survivors, and hundreds of soldiers have been sent to try to reach isolated communities in the mountainous interior of the state.

Roads in mountainous regions were blocked by rockfalls and landslides, hampering the rescue efforts, and some damage has been reported to bridges. Electricity and telephone lines were disrupted and emergency workers are scampering to restore vital services.

Mexican President Vicente Fox surveyed the region by helicopter and on foot, and promised to rebuild hundreds of homes that were destroyed in the disaster. International aid is pouring into the region, greatly assisting in the daunting task of rebuilding.

Past earthquakes of this magnitude have killed hundreds and even thousands of people, and experts are surprised that the casualty assessment has been so light.

Additional information links

• Seismo-Watch - links for more Central America information
  • Earthquakes in 2003, M 6.0 and greater
• Preliminary Earthquake Report, National Earthquake Information Center
  • Earthquake Location
  • Historical Seismicity Map
  • Moment Tensor
  • Phase Data
• IRIS Data Management Center Special Report Page
• EQNet Special Report

Mainstream media news reports:

• See an extensive list of breaking wire news stories. Check the EQNews archive for earlier reports.