Images

Pit dug for collection of geologic data and observations, such as geochronology samples to determine the age of faulted surfaces and documentation and dating of faulted recent sediments of the Puya Fault in northern New Mexico, 4/25/2023.

Although most economic loss is concentrated along the west coast, the distribution of relative earthquake risk, as measured by the Annualized Earthquake Loss Ratio (AELR), is spread throughout the country and it reinforces the fact that earthquakes are a national problem.

Map showing distribution of average annualized earthquake loss by region. The high concentration of loss in California and the West Coast is consistent with that region’s high seismic hazard, significant population, and building exposure. 

Landslides near the 2017 Thomas fire burn area that initiated during a series of atmospheric river events in December 2022 and January 2023.  

University of Puerto Rico-Mayagüez students Estefania Vicens, Tania Figueroa, Anishka Ruiz, Cesar Rodriguez, and Kimberly Maisonet stand next to completed landslide monitoring station at Yauco, Puerto Rico, part of the Landslide Monitoring Network.

Estefania Vicens, Tania Figueroa, Kimberly Trahan, Victor Ortega stand next to completed Mayagüez monitoring station, part of the Puerto Rico Landslide Monitoring Network

Completed landslide monitoring station at Ponce, Puerto Rico among the palms. One of the sites in the Puerto Rico Landslide Monitoring Network.

Example of a landslide that initiated within the footprint of the 2019 Cave Fire during the 9 January 2023 rainstorm. The landslide source area is shown in the upper left of this image. The debris-flow runout path is shown in the center and lower right of this image.

The large HTHH volcanic explosion created fast low-frequency pressure waves that penetrated about 3.1 miles/5 kilometers into the shallow crust (shown in yellow). Wind and small explosions (shown in blue) create shorter pressure waves that only penetrate down about 328 feet/100 meters.

The waveforms of the ground motion recording and the pressure sensor recording from a station with both types of instruments (see second image above) match up, indicating that the pressure waves are causing the ground (crust) to deflect.

Debris-flow deposits downstream of the 2022 Pipeline Fire burn scar, north of Flagstaff, Arizona.

The June 28, 2022, Chaos Canyon debris slide with main features labeled. Horizontal distance from the middle of headscarp to the middle of toe is about 585 m. North is towards the right side of the photograph.

The USGS “Heil Ranch” site is located in the Arapahoe-Roosevelt National Forest in Colorado. The site consists of instrumentation monitoring the rainfall and soil moisture.

This image of the Los Angeles region combines this information to predict the total amplification expected in future earthquakes from local geologic conditions or site effects.

A diagram showing a slice of the Earth's lithosphere, including continental crust, oceanic crust, asthenosphere, and the upper mantle.

An illustration showing two stick figures doing basement excavations, one with a frown that excavated into the labelled hard, stable bedrock on the left and the other with a smile that excavated above the labelled bedrock surface.  

A diagram of a blind thrust fault resulting in ductile rock layers folding over the fault and leaving the fault under the surface.

A diagram showing three stress types: tensional stress, compressional stress, and shear stress. 

Cross-section of the Earth with lithosphere, mantle, and the core divided into the metallic liquid core and the solid inner core.

En echelon shears crossing street, Hayward Hayward, California. The street shows en echelon shears crossing Foothill Boulevard in San Leandro, just to the north of Hayward. Here the shear zone is quite narrow.

Diagram showing the epicenter and hypocenter. 

The epicenter is the point on the earth's surface vertically above the hypocenter (or focus), point in the crust where a seismic rupture begins.