Map showing location of major faults and offshore basins of the San Francisco area, from the study Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California.
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Sometimes.
Earthquakes, particularly large ones, can trigger other earthquakes in more distant locations though a process known as dynamic stress transfer/triggering. This means that the energy from the seismic wave passing through can cause a new earthquake, usually in already vulnerable locations prone to frequent earthquakes (e.g., volcanic regions). Examples of large events that triggered distant seismicity include the 1992 M7.3 Landers earthquake, 2002 M7.9 Denali earthquake, and the 2004 M 9.1 Sumatra earthquake that ruptured an area ~1300x200 square km, and triggered aftershocks from northern Sumatra to just south of Myanmar.
If a triggered earthquake is within a distance of about 2-3 fault lengths of the fault rupture associated with a mainshock, the earthquake is considered to be an aftershock, not a triggered event.
The fault length is related to the earthquake size:
Learn more:
Map showing location of major faults and offshore basins of the San Francisco area, from the study Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California.
Map showing location of major faults and offshore basins of the San Francisco area, from the study Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California.
by Morgan Page, USGS Research Geophysicist
by Morgan Page, USGS Research Geophysicist
Map of southern Alaska showing the epicenter of the 1964 Alaska Earthquake (red star).
Map of southern Alaska showing the epicenter of the 1964 Alaska Earthquake (red star).
Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.
Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.
Map showing location of major faults and offshore basins of the San Francisco area, from the study Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California.
Map showing location of major faults and offshore basins of the San Francisco area, from the study Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California.
by Morgan Page, USGS Research Geophysicist
by Morgan Page, USGS Research Geophysicist
Map of southern Alaska showing the epicenter of the 1964 Alaska Earthquake (red star).
Map of southern Alaska showing the epicenter of the 1964 Alaska Earthquake (red star).
Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.
Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.