The 17 May 2012 M4.8 earthquake near Timpson, East Texas: An event possibly triggered by fluid injection

Journal of Geophysical Research B: Solid Earth
By: , and 



This study summarizes our investigation of the 17 May 2012 MW-RMT4.8 earthquake near Timpson, Texas, the largest earthquake recorded historically in eastern Texas. To identify preshocks and aftershocks of the 17 May event we examined the arrivals recorded at Nacogdoches (NATX) 30 km from the 17 May epicenter, at nearby USArray Transportable Array stations, and at eight temporary stations deployed between 26 May 2012 and mid-2013. At NATX we identified seven preshocks, the earliest occurring in April 2008. Reliably located aftershocks recorded by the temporary stations lie along a 6 km long NW-SE linear trend corresponding to a previously mapped basement fault that extends across the highest-intensity (MMI VII) region of the 17 May main shock. Earthquakes in this sequence are relatively shallow—with focal depths ranging from 1.6 to 4.6 km. Evidence supporting these depths include: hypocentral locations of exceptionally well-recorded aftershocks, S-P intervals at the nearest stations, and comparisons of synthetics and observed seismograms. Within 3 km of the linear trend of aftershock activity there are two Class II injection disposal wells injecting at 1.9 km depth beginning in August 2006 and February 2007, with injection rates averaging 42,750 m3/mo and 15,600 m3/mo, respectively. Several observations support the hypothesis that fluid injection triggered the Timpson sequence: well-located epicenters are situated near a mapped basement fault and near high-volume injection wells, focal depths are at or below the depths of injection, and the earliest preshock (April 2008) occurred after the onset of injection in 2006.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The 17 May 2012 M4.8 earthquake near Timpson, East Texas: An event possibly triggered by fluid injection
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2013JB010755
Volume 119
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description 13 p.
First page 581
Last page 593
Country United States
State Texas
City Timpson