Monitoring Induced Earthquakes at the Preston New Road Shale Gas Site, Blackpool, UK

Session: Earthquake Source Parameters: Theory, Observations and Interpretations
Type: Oral
Date: 4/30/2020
Time: 09:00 AM
Room: 120 + 130
Description: 

The shale gas site at Preston New Road (PNR), Blackpool, UK, is the first hydraulically fractured well in the UK since activity was suspended in 2011. The University of Liverpool (UoL), in conjunction with the British Geological Survey (BGS) and the well operator (Cuadrilla Resources), have continuously monitored seismic activity at PNR prior to and throughout operations. During this time two wells were completed; however, both led to levels of activity that exceeded the strict traffic light system (red = M_L 0.5). The activity culminated in M_L 1.5 and M_L 2.9 events in August 2018 and November 2019, respectively. Both events caused fracking operations to be suspended, with the latter resulting in an indefinite moratorium. Clearly, this highlights the need for further study of seismic activity at PNR. Here, we utilize more than one year of continuous data, recorded by 26 broadband stations (HH, Aug 2018 - Nov 2019), to compile a new, high-resolution earthquake catalog.

To generate our catalog, we first use a recursive STA/LTA coincidence detector to build a database of earthquake templates, which are later employed to minimize our detection threshold by applying matched filter techniques. To achieve high resolution earthquake locations, we relocate the events using double difference techniques and differential times from both catalog and cross correlation data. Uncertainties in earthquake locations are estimated using a bootstrap method, whereas the effect of the network geometry on the locations is examined using the jackknife technique. Finally, we calculate moment magnitudes (M_w) for events in our new catalog via spectral modeling and derive an M_L - M_W scaling relationship, which is compared with other relations.

Presenting Author: James Holt

Authors