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Maryland Seismicity: Insights From Moment Tensor Inversion With a Sparse Seismic Network

Description: 

Small, 1.5 – 3.6 magnitude earthquakes occur up to several times a year in Maryland and the surrounding areas. These earthquakes are mostly confined to the Piedmont geological province. Because of their small size and the sparsity of permanent seismic stations operating in the region, source characterization is difficult, and even first motion mechanisms are rarely available. Therefore, it is not known how these events relate to local geology and pre-existing faults, or whether their mechanisms are consistent with local or regional stress fields. To better understand the nature of Maryland seismicity, we investigate the source depths and mechanisms for a cluster of M ~ 2 earthquakes by performing full waveform moment tensor inversions.
The velocity structure used to construct Green’s functions is constrained using a collection of local 1D models as well as an inversion from surface wave dispersion data. The range of reasonable 1D models is used to assess the sensitivity of moment tensor inversion to variations in velocity structure.
Additionally, we systematically assess moment tensor error resulting from perturbations introduced to the velocity model, as a function of station position.
We interpret the focal mechanisms in the context of information available on local and regional tectonic stresses and faulting regimes. Finally, we discuss the implications of our results for seismicity across the Mid-Atlantic region of the United States.

Session: Earthquakes, Lithospheric Structure, and Dynamics in Stable Continental Region [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Yuval

Student Presenter: Yes

Invited Presentation: 

Poster Number: 69

Authors