Abstract
Seismometers were installed in the Haynesville basin and Sabine uplifts
in northwestern Louisiana and eastern Texas with the purpose of tracking
earthquakes in correlation with hydraulic fracturing and wastewater
injections in the area. Project ISLA (Investigating Seismicity of
Louisiana) consists of 10 seismometers installed in June 2019 and 4 in
late 2020 combined to discover baseline seismicity in the area. This
study which analyzes earthquakes from April 2021 between 2.5 and 3.2 in
magnitude uses data extracted from the ISLA seismic array in Northwest
Louisiana from 2019 to present. Additionally, in an attempt to decrease
azimuthal gaps data is also extracted from permanent TEXNET and U.S.
array stations in Arkansas and Oklahoma. Absolute locations are
determined using hypoinverse and the velocity model from East Texas.
Focal mechanisms are determined by picking the polarity of P arrivals
and plotting them on a stereonet, using take off angles and azimuths
from hypoinverse results. Using first motion data, nodal planes are
determined, and focal mechanism solutions are revealed. Analyses will
result in the ability to understand focal mechanisms and earthquake
locations in the Haynesville basin and Sabine uplifts in the context of
Mesozoic rift structures, hydraulic fracturing, and wastewater
injections.