Images

During the first week of April a different type of seismic signature was showing up on seismograms from Mount St. Helens. On April 1 the first weak harmonic tremor was detected. Stronger bursts of harmonic tremor were recorded on the 2nd. The seismogram above is an example of harmonic tremor recorded at seismic station RAN on April 2.

Charles Richter, inventor of the Richter Scale.

Seismology is the study of earthquakes and the structure of the earth, by both naturally and artificially generated seismic waves.

Photo of deformed rock. Deformation is a change in the original shape of a material. When we are talking about earthquakes, deformation is due to stress and strain.

The May 12, 2008, Great Sichuan Earthquake, also called the Wenchuan Earthquake, occurred at 14:28 local time, in Sichuan Province, China. The earthquake magnitudes were Mw = 7.9 (USGS), Ms = 8.0 (Chinese Earthquake Administration). The epicenter was 80 km west-northwest of Chengdu, the capital city of Sichuan province.

The May 12, 2008, Great Sichuan Earthquake, also called the Wenchuan Earthquake, occurred at 14:28 local time, in Sichuan Province, China. The earthquake magnitudes were Mw = 7.9 (USGS), Ms = 8.0 (Chinese Earthquake Administration). The epicenter was 80 km west-northwest of Chengdu, the capital city of Sichuan province.

Damage to a house in Louisa County, Virginia, after a magnitude 5.8 earthquake on August 23, 2011.

Damage to a house in Louisa County, Virginia, after a magnitude 5.8 earthquake on August 23, 2011.

Damage to a house in Louisa County, Virginia, after a magnitude 5.8 earthquake on August 23, 2011.

Chimney damage to a house in Louisa County, Virginia, after a magnitude 5.8 earthquake on August 23, 2011.

Following the devastating 2010 Haiti earthquake, the USGS has been helping with earthquake awareness and monitoring in the country, with continued support from the U.S. Agency for International Development (USAID).

A Cessna Grand Caravan airplane took measurements over Virginia's Louisa, Goochland and Fluvanna counties. The data collected will help USGS scientists locate buried geologic features associated with the August 23, 2011 earthquake and its aftershocks. Surveys were conducted from 7/15- 7/25.

A Cessna Grand Caravan airplane took measurements over Virginia's Louisa, Goochland and Fluvanna counties. The data collected will help USGS scientists locate buried geologic features associated with the August 23, 2011 earthquake and its aftershocks. Surveys were conducted from 7/15- 7/25.

A Cessna Grand Caravan airplane took measurements over Virginia's Louisa, Goochland and Fluvanna counties. The data collected will help USGS scientists locate buried geologic features associated with the August 23, 2011 earthquake and its aftershocks. Surveys were conducted from 7/15- 7/25.

USGS geophysicist Anjana Shah stands next to a Cessna Grand Caravan airplane that took measurements over Virginia's Louisa, Goochland and Fluvanna counties. The data collected will help USGS scientists locate buried geologic features associated with the August 23, 2011 earthquake and its aftershocks. Surveys were conducted from 7/15- 7/25.

Full view of the ground with the San Andreas fault running through the middle of the image. A 30 foot steam offset from the 1857 earthquake can be seen near the right edge of the image.

Photo showing the kite that is suspending the camera over the San Andreas Fault.

The earthwork in context of the small town of Parkfield, CA.

Photo taken from a kite-lofted camera, showing the shake table and control bunker.

3-minute exposure of Parkfield Cafe (and shake table) entrance at night.

Looking straight up from the center of the Shake Table.

An 8.5-minute exposure taken on a moonless night with a blue-gel'd flashlight to fill in the top of the shake table.