Dynamic earthquake triggering in the continental U.S.
Seismological studies have classified the changes in field stress required to trigger remote earthquakes into two basic types: static and dynamic triggering. Static triggering mainly originates from geological faults already present in certain tectonic environments and they could be originated due to continental crust, subduction zones or even from a highly seismicity zone. Dynamic triggering occurs when an event (earthquake) has been induced by the passing of seismic waves from a large main shock located at least two or more fault lengths from the epicenter of the main shock. This study investigates details of dynamic triggering not seen in previous studies. This investigation focuses on gathering and analyzing data to detect and tabulate high-frequency detections (HFD) that might indicate locally triggered earthquakes on the United States continent. In particular, data in form of seismic waveforms was downloaded and collected from EarthScope's USArray, which has an active Transportable Array (TA) station program that emphasizes the broadband compilation of geophysical data across the continental U.S. All seismic waveforms were gathered using ∼400 different seismic stations primarily focusing on two types of data: local events with a magnitude M≥4.0, and teleseismic events with magnitude M≥6.5. Triggered events were identified inherent in the event's frequency spectra using an automated detector (Antelope software) and a series of filters by examining both the amplitude and frequency of the waves responsible for triggering. The results will help provide for a better understanding of the physical mechanisms involved in dynamic earthquake triggering and also will help identify zones in the U.S. continent which may be more susceptible to these kinds of events. ^
Cerda, Ibrahim, "Dynamic earthquake triggering in the continental U.S." (2012). ETD Collection for University of Texas, El Paso. AAI1533215.