Images

Map of the United States and its territories showing 2024 International Building Code Seismic Design Categories and Risk Categories.

The graphic shows the last 17 solar cycles and their related increased sunspot activity. A solar cycle is a roughly 11-year periodic change in the Sun characterized by variations in the number and intensity of sunspots, as well as a flipping of its magnetic poles.

An example of Bayesian updating of productivity parameter (a-value) for the 2010 Mw 8.8 Maule, Chile, earthquake. Immediately following the earthquake, the SZ-GENERIC region-specific a-value distribution can be used.

Screenshot of the Aftershock Forecast for an earthquake in California, showing the information box at the top of the forecast and the four tabs of forecast information.

Aftershock Forecast Sequence-Specific Model Parameters equation 

The probability distribution for the number of aftershocks, P(N), and the forecast can then be computed using the same procedures as for the generic model, using P_seq-spec(a) instead of P_generic(a).

Equation 2 for the Aftershock Forecast probability distribution to compute the forecast

A low-angle aerial view of the vents where episodic fountaining has been occurring since the start of the ongoing Kīlauea summit eruption on December 23, 2024. A white plume of volcanic gas rises from the north vent (center right) and south vent (center left) cones in the southwest corner of Halema‘uma‘u crater, as viewed during a monitoring overflight.

Icon used to refer to ShakeMap on Product landing pages. For example use, see https://staging-earthquake.usgs.gov/data/pager/background.php.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, scrolled to the bottom of the page. The mainshock is shown with a yellow star on top of its circle; other earthquakes in the forecasting region are also shown colored by time of occurrence.

Aftershock Forecast Model parameters screenshot of the Aftershock Forecast Overview page

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, and “M4+” and “Show All” selections for magnitude and forecast duration.
 

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Commentary” tab selected.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, and “M4+” and “Show All” selections for magnitude and forecast duration.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Forecast Table” tab selected.

Two example aftershock sequences, from southern California, that illustrate the three general rules of aftershocks. A circle shows each aftershock's time of occurrence (horizontal axis) and magnitude (vertical axis). The larger-magnitude M6.7 Northridge earthquake is followed by many more aftershocks than the smaller M5.1 La Habra earthquake.

Screenshot of the Overview webpage for an earthquake in California. The “Aftershock Forecast” card is at lower center.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, and “Show All” and “1 Month” selections for magnitude and forecast duration.

Ven diagram of risk as the intersection of hazards and society. This illustrates the logical relationships between two or more sets of items. 

NATIONAL LANDSLIDE SUSCEPTIBILITY MAP

POSTFIRE DEBRIS FLOW SCIENCE

The U.S. Geological Survey helps local, state, and federal agencies assess debris flow hazards in recently burned areas. We provide information about the likelihood of debris flow activity, where they might happen, and how big they might be.

DEBRIS FLOW ASSESSMENTS

LANDSLIDE SAFETY

If your home or property was damaged by a landslide from Hurricane Helene, be aware of the warning signs of future landslide activity

WATCH FOR WARNING SIGNS

Signs a landslide may be moving include: