Trevor Smith, UCSB graduate student, will give a talk at Speakers Club today entitled The Detection of Low Magnitude Events Induced by Hydraulic Fracturing: Can we distinguish them from normal earthquakes? The talk is at 2:00 PM (today, Thursday) in Webb Hall 1100.
Hydraulic Fracturing is a well stimulation technique used by the oil industry to extract hydrocarbons from a reservoir with low permeability. When the well is stimulated the rock is fractured and the fracture network can be inferred from the locations of induced micro-earthquakes. However, these events are small in magnitude and often difficult to detect, particularly in the noisy environment created by the injec- tion processes. Here we have applied a newly developed de- tection algorithm, Match & Locate (M&L, Zhang and Wen 2015), to improve the catalog of induced seismicity during two hydraulic fracture experiments. M&L utilizes waveform cross-correlation to enhance the signals amplitude relative to the noise and we find at least twice as many earthquakes. The improved earthquake catalog is subsequently used to study the magnitude-frequency relationship. We find that the dis- tribution of induced seismicity does not exactly follow the Gutenberg-Richter Law, which can be used to distinguish in- duced seismicity from normal seismicity.