Tectonic Summary

The March 26, 2020 M 5.0 west Texas earthquake occurred as the result of shallow normal faulting about 40 km west of the town of Mentone, Texas. The earthquake occurred within the interior of the North America plate, far from any plate boundaries. The preliminary focal mechanism solution for the earthquake indicates rupture occurred on a moderately dipping fault plane striking roughly east-west. The earthquake location aligns with old faults in the basement and is nearly 75 km east of currently mapped north-south oriented Quaternary active faults. Further analysis and possibly fieldwork are required to associate this earthquake with an existing or unmapped fault.

On Aug 1, 1975, a magnitude 4.8 earthquake occurred approximately 30 km to the south of this earthquake; however, a detailed history of small (less than magnitude 3) earthquakes in this region is not well know because the region was not well covered by seismometers until recent years.

Locations across the central and eastern United States (CEUS) have been experiencing an increase in the number of earthquakes over the past two decades. Scientific studies have linked most of this increase to human (induced) activity, predominantly related to wastewater injection in deep disposal wells in several locations. However, other mechanisms such as fluid withdrawal, enhanced oil recovery, or hydraulic fracturing processes can also result in induced earthquakes. In addition, regions with frequent induced events may also be subject to damaging earthquakes that would have occurred independently of human activity.

Making a strong scientific case for a causative link between a particular human activity and a particular sequence of earthquakes typically involves special studies devoted specifically to the question. Such investigations usually address the process by which the suspected triggering activity might have significantly altered stresses in the rocks at the earthquake source, and they commonly address the ways in which the characteristics of the suspected human triggered earthquakes differ from the characteristics of natural earthquakes in the region.

Event Details

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