Numerous factors influence the potential for the hydraulic fracturing and wastewater disposal activities used for natural gas development to cause earthquakes, a phenomenon known as induced seismicity.
Since 2012, Geoscience BC has been funding induced seismicity research to better understand when, where and why induced seismicity occurs and to inform industry, government and community decisions so that the likelihood of future induced seismicity can be reduced.
In 2018, the BC Oil and Gas Commission (OGC) designated the Kiskatinaw Seismic Monitoring and Mitigation Area (KSMMA) to “investigate a series of low-level seismic events” arising from hydraulic fracturing. Hydraulic fracturing pumps a mixture of sand, water and additives into rocks, causing them to fracture and release a flow of natural gas. An array (network) of seismographs – highly sensitive instruments that record seismic waves – were installed to monitor the ground movement in the KSMMA.
The existing public seismograph array is widely spaced over a large area to capture higher magnitude, regional seismicity patterns. This project installed more closely spaced sensors (a ‘dense array’) because studies have found that a dense array can provide a more detailed picture of seismicity. Data from a dense array can be analyzed by researchers to create models to inform regulatory practice and to promote responsible natural gas development in BC’s Northeast Region.
This Energy project fits under Geoscience BC’s Strategic Objective of ‘Facilitating Responsible Natural Resource Development’ and our goal to:
- Maintain joint research with partners examining seismicity induced by hydraulic fracturing in northeastern BC to provide new science to better understand induced seismicity, mitigate risks and further improve regulation and industry practices.
Specifically, this project:
- generated new, public ground motion monitoring data in the KSMMA;
- improved calibration of the ground-motion prediction equations to inform work in the area and update previous studies;
- researched fault response to hydraulic fracturing and kinematics of fault rupture; and
- provides real-time seismic data to researchers, the public, operators and regulators.
The public data generated by this project can be used by researchers to help generate models to help predict when, where and why earthquakes associated with hydraulic fracturing can occur. Specifically, it created new:
- data that can be used to assess individual seismicity and regulatory requirements in the KSMMA;
- trained new subject matter experts (SMEs) / highly qualified persons (HQPs); and
- generated new, peer reviewed literature to guide future practices and research.
The dense seismograph array is in the KSMMA, between Dawson Creek and Fort St John in BC’s Northeast Region.
What Was Found
This project installed and operated a strategically located dense seismograph array of 15 stations, consisting of 13 broadband seismometers and 2 accelerometers, in the KSMMA.
Seismicity data and real-time data streams collected by the array were processed and analyzed by researchers at the University of Calgary and Nanometrics. From January 22, 2020 to March 31, 2021 (inclusive), the average local magnitude of events detected using the network and available public stations was 0.5, with a maximum recorded local magnitude of 3.19. In total, 9,740 events were detected and located.
The researchers concluded that the availability of real-time continuous data from a dense array of stations could be used to generate automatic shakemaps (maps of ground motion intensity), which are helpful to better understand local and seasonal variations in ground motion due to seismic events. The researchers also found that the seismicity data can help identify and map subsurface structures, which helps to improve analysis of geological susceptibility to induced seismicity.
The raw data collected by the monitoring network has been released to the public through the Incorporated Research Institutes in Seismology (IRIS) following a running 91-day embargo period.
Geoscience BC funding for the dense array ends in July 2021, with additional funding from the Natural Sciences and Engineering Research Council (NSERC) of Canada extending the research program and allowing the seismograph network to be maintained until early 2022. Details about NSERC funding can be found here.
This project is also part of the Microseismic Industry Consortium.