Automatic detection of microearthquakes in borehole records:
For the first time, an automatic detection workflow was successfully
implemented to seismological data recorded in deep boreholes situated in
the Koyna-Warna region. This workflow allowed identification of about
twice as many events as compared to the time-consuming manual data
processing. Also, a two-stage grid-search algorithm provided
additionally better constraints on the absolute event locations.
Further, a relative location process of these events using a waveform
similarity approach was performed. These new events provided a tighter
clustering than was obtained earlier. The seismicity trend correlates
well with the anomalies obtained from airborne lidar studies. It is
believed that the improvements achieved in detection and locations of
microearthquakes using the borehole seismograms will provide better
understanding of the RTS of the Koyna-Warna region (Shashidhar et al.,
2020).