2025/02/11 by Stephen Glenn Hilfiker, John E. Ebel · 1 voice
Earth and Planetary Sciences · Computer Science · #earthquake and tectonic studies #Seismology and Earthquake Studies #Seismic Waves and Analysis
paper · doi:10.2113/2024/lithosphere_2024_129
openalex publication_date 2025/02/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/26
Abstract The August 23 , 2011 MW 5.8 Mineral, Virginia, earthquake, the largest magnitude event recorded in the Central Virginia Seismic Zone, caused widespread damage and generated a lengthy and well-recorded aftershock sequence. Over 1600 aftershocks, recorded using a dense network of seismometers in the 4 months following the mainshock, offer an important opportunity to study the fault structure responsible for the postmainshock seismicity and hence to infer details about the mainshock rupture. In this study, the relative locations of well-recorded aftershocks were calculated to generate a high-resolution model of the fault structures on which the aftershocks took place. Moment-tensor inversions of the P and S amplitudes of dozens of the aftershocks at various locations in the aftershock zone were used to generate focal mechanisms for events on the different fault structures that were imaged by the relative location analysis. These focal mechanisms reveal both normal and thrust faulting on the fault structures. Results from these two analyses map the structures responsible for the aftershock sequence with high spatial resolution. The fault structures responsible for the aftershocks consist of two primary planes, one smaller planar feature, and some off-fault seismicity near the intersection of the two primary planes. The fault planes imaged in this study all appear to be part of the Quail Fault Zone.