Software for Download
Several USGS scientists have authored software packages for use in their research. These programs include stress-triggering software, a general purpose 2-D seismic seismic ray tracer, conversions from UTM to Lat/Long, and others. Descriptions of these programs and access to downloadable versions are now available on the web.

USGS Scientific Expedition: Earthquake in Turkey - 1999
Scientists and engineers from the U.S. Geological Survey departed for the epicentral region on August 19, 1999, less than 2 days after the quake occurred, to join in an international scientific effort that will deploy seismic and geodetic instruments, make geologic field measurements and assess and record the structural damage.

Loma Prieta Earthquake 10th Anniversary Review (1999)
We review the scientific progress and accomplishments that have been made in understanding and mitigating the earthquake hazard. We present a retrospective of the earthquake, including many photos.

Is Earthquake Prediction Possible?
Earthquake prediction is a controversial topic. Now, the international journal Nature brings us a moderated, on-line debate among 8 seismologists, including the USGS's Andrew Michael.

1906 San Francisco Earthquake
In-depth reports from seismological and societal perspectives including background, casualties, damage, and what was learned scientifically. Lots of great photos and eyewitness accounts.

Effect of Soil Type on Shaking Hazard
The type of soil at a site affects the strength of seismic shaking there. Softer soils amplify the shaking. Learn about this effect and use an interactive map to determine the soil type at any site in the San Francisco Bay area.

The 1998 USGS Expedition to Mongolia
Discover what Mongolian earthquakes can reveal about earthquake hazards in the U.S.

Northridge, California, Earthquake Studies
These pages summarize the results of numerous scientific investigations into the nature of the earthquake source, the shaking it produced and its damaging effects in the Los Angeles area.

Speeding Earthquake Disaster Relief
Scientists and emergency managers have found new ways to speed and improve relief efforts with the rapid availability of earthquake information from seismograph networks.

Building Safer Structures
By monitoring how structures respond to earthquakes and applying the knowledge gained, scientists and engineers are improving the ability of structures to survive major earthquakes.

The Mississippi Valley - "Whole Lotta Shakin' Goin' On"
In the winter of 1811-12, the central Mississippi Valley was struck by three of the most powerful earthquakes in U.S. history. Even today, this region has more earthquakes than any other part of the United States east of the Rocky Mountains.

Seismology at the Science Fair
Earthquakes provide lots of great opportunities for science fair projects. Do Lost Pet Ads Predict Earthquakes? Will Overstressed Bridges Survive Earthquakes?

Studying Earthquakes
Earthquake research developments at the USGS Earthquake Hazards Team in Menlo Park, California. Sections on seismology, strong-motion seismology, crustal structure, crustal deformation, geology, bore hole geophysics and rock mechanics.

Listening to Earthquakes
This page explores the relationship between seismic waves and sound waves - in this case, music. Requires good loud speakers or headphones on your computer.

GPS and Earthquake Hazard Reduction
Introduction to the role of Global Positioning Satellite data in earthquake studies.

Gurvan Bulag Thrust Fault
Summary of the 1997 USGS expedition to Mongolia to study the 1957 Gobi Altay earthquake - a 23-km-long thrust rupture - which is considered a possible analog for future earthquakes in southern California.

Late Night Musings of an Earthquake Seismologist
A USGS seismologist/homeowner reflects on the perception of earthquake risk in the wake of the 1994 Northridge, California, earthquake.

Hawaiian Earthquake Activity
Earthquakes in Hawaii are closely linked to volcanism. They are an important part of the processes of island-building that have shaped the Island of Hawaii and the other Hawaiian Islands. Thousands of earthquakes occur every year beneath the Island of Hawaii.

Thickness of the Outer Layer of the Earth
Contour map of the thickness of the Earth's crust, and a tour of the data and methods used to produce it.

Measuring Plate Motions with GPS
Maps showing velocities of survey stations determined using data from the Global Positioning Satellite system. For California & Nevada and for North America.

Crustal Deformation Measurements
The Earth's surface near active faults deforms before, during and after earthquakes and near active volcanoes as a consequence of eruptions. This deformation can be observed as relative movement of points on the Earth's surface, ground tilt, ground strain, and fault slip (creep). Measurements from San Francisco Bay, San Juan Bautista, Parkfield, Long Valley and southern California.

Deformation and Stress-Change Modeling and Monitoring
A research page focusing on geodetic modeling using GPS and InSAR data; and earthquake stress triggering and stress transfer analyses.

Earthquakes, Minerals And Me: An Interview with Robert Wallace
A USGS seismologist/homeowner reflects on the perception of earthquake risk in the wake of the 1994 Northridge, California, earthquake.

Finding the Starting Point of Earthquakes
A primer on the method seismologists use to determine the location and time of an earthquake from signals recorded by seismometers.

Next Big Earthquake in the San Francisco Bay Area
A very readable and thorough review of the probability of an earthquake and how to prepare for it. Written in 1989 after the Loma Prieta earthquake.

Weekly Seismicity Reports
View online or sign up for a free email subscription to these weekly summaries of earthquake activity in northern California.

Potential for Large Earthquakes in Northern California
Report and database on the active faults and geologic information about them, including slip rate, strain rate and seismicity. USGS Open-File Report 96-705.

What Happens When an Earthquake Occurs
How we process the data from an earthquake: from network detection, telemetry, and calculation of its location, magnitude and time, to swiftly moving the results to our real-time maps.

California, Nevada, and Baja California Earthquakes: 1769-Present
Compilation of earthquakes (magnitude ~6 and larger) exerpted from USGS Professional Paper 1515 and updated. By William L. Ellsworth.

Earthquakes and Gunshots
An adaptation of seismological methods to locate earthquakes is used now to locate gunshots. This system helps police rapidly respond to illegal gunfire and reduce crime in urban neighborhoods.

Earthquakes in Alaska
A detailed map showing the overall geologic setting in Alaska that produces earthquakes. Shows faults, plate motions and major earthquakes.

Earthquake Fact Sheets
These colorfully illustrated, readable summaries highlight a variety of earthquake hazard and risk-mitigation topics.