This is about earthquakes caused by injecting during fracturing, not from the use of disposal wells (which has already been reported).
The investigation has concluded that the events observed within remote and isolated areas of the Horn River Basin between 2009 and 2011 were caused by fluid injection during hydraulic fracturing in proximity to pre-existing faults.
BC’s Horn River Basin, a huge source of natural gas — and C02 emissions. Also see BC’s burgeoning CO2 emissions problem
This report provides the results of the BC Oil and Gas Commission’s (Commission) investigation into anomalous seismicity within geographically confined and remote areas in the Horn River Basin between April 2009 and December 2011. The investigation was commenced immediately after the Commission became aware of a number of anomalous, low-level seismic events which were recorded by Natural Resources Canada (NRCan) near areas of oil and gas development. Only one of the events under investigation had been reported by NRCan as “felt” at the earth’s surface.
Between April 2009 and July 2011, 31 seismic events were recorded and located by NRCan in the Etsho area of the Horn River Basin in northeast British Columbia (Figure 1). Another seven events were recorded near the Tattoo area between Dec. 8 and Dec. 13, 2011. The observed events ranged in magnitude between 2.2 and 3.8 ML on the Richter scale as recorded by NRCan (Table 1). A search of the areas in the National Earthquake Database from 1985 to present shows no detected seismicity in the Horn River Basin prior to 2009. Two events (1985/09/04, 3.1ML and 1986/09/28, 2.9ML) located approximately 160 km south and southwest of Fort Nelson were detected by the Canadian National Seismograph Network (CNSN). This suggests that similar events occurring in the Horn River Basin could have been recorded. Two NRCan seismograph stations, part of the CNSN, are currently operational in northeast British Columbia. The Bull Mountain station near Hudson’s Hope became operational in January 1998 and the Fort Nelson station came online in 1999. Magnitudes have been processed and reported down to approximately 2.0 ML in the Horn River Basin since deployment of these two stations. Smaller events may have occurred and gone undetected due to the detection limitations of the CNSN. While the full extent of historical seismicity is not known, the April 2009 to December 2011 Etsho and Tattoo events are considered anomalous events when considered in full context. Download report.