Low Yield Seismic Source Analysis Using Local and Regional Observations
Low-yield explosion monitoring introduces new challenges to the current approach to estimating source location, magnitude, and discrimination. Small sources require nearby short period observations, which have an increased sensitivity to geologic heterogeneity, poor signal-to-noise ratios, and in many cases are sparse. Local and regional short periods observations from small shallow seismic sources can be dominated by a regional phase shear waves and Rayleigh waves. Using teleseismic surface wave observations, Cleveland & Ammon  and Cleveland et al.  show the value of using surface waves to estimate precise, relative locations in regions without a nearby seismic network. Using common-station, nearby-event cross correlation time-shift measurements, much of the complexity in wave propagation caused by regional geological heterogeneity is removed (or at least, greatly reduced). In this work, we extend surface wave relocation methods to estimate precise relative locations of small (local magnitudes from 1 to 3) mine blast events across Pennsylvania using local and near-regional distance observations (out to 300 km in distance). We also exploit the cross correlation amplitude to estimate more precise relative magnitudes (actually log-moments) and develop a more consistent relationship between explosion yield and relative magnitude for various mines throughout the Commonwealth. Our locations are precise enough to allow us to image a time-dependent migration of a mine wall in north-central Pennsylvania. In west-central Pennsylvania, application of the relative location approach collapses a diffuse distribution of small-magnitude industrial events into five discreet clusters associated with particular operations in the area. The work demonstrates that cross correlation methods have the potential for achieving high precision relative location and magnitude estimates from local and regional observations of low yield seismic sources.
|Work Title||Low Yield Seismic Source Analysis Using Local and Regional Observations|
|License||All rights reserved|
|Deposited||June 07, 2018|
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