New scientific approach uses seismic data to predict increased earthquake risk over shorter periods

Researchers in Canada are one step closer to being able to predict increased earthquake risk over periods as short as five to 10 years.
The new method suggests potential seismic activity over the next five years near Ottawa, Montreal and Quebec City. Over the next eight years, it suggests significant seismic activity in British Columbia in Richmond, Delta and north of Vancouver.
Kristy Tiampo spoke about the new approach, which employs a ‘Pattern Informatics (PI) Index,’ at the Institute for Catastrophic Loss Reduction’s Friday Forum workshop series in Toronto. Tiampo is an NSERC and Benfield/ICLR industrial research chair in earthquake hazard assessment based at the University of Western Ontario.
The idea behind the PI Index is that every time an earthquake occurs, it changes the stress loading on nearby earthquake faults. Smaller earthquakes of Magnitude 3 thus act as “sensors” for where major earthquakes may later occur.
“Over a series of large events, we would start to know what the stress changes are, not because of an estimate, but from the actual numbers of earthquakes that happen in particular areas,” Tiampo said. “And we can use that as a sensor or indicator of what the actual underlying stresses do. It’s coming up with a time evolution of stresses in the system.”
The PI Index uses data collected on seismic activity, which helps identify future stress points. Anomalous seismic activity is measured against a long-term regional background rate. Areas where anomalous seismic activity is recorded correspond to the increased probability of an event in that location.
Tiampo said the effectiveness of the PI method for detecting potential earthquake activity is dependent upon the quantity and quality of the seismic data gathered. The better the data, the better the forecast. And whereas California has thousands of instruments measuring seismic activity, Canada, in contrast, has “hundreds” of such instruments.
Based on data collected during her research, Tiampo showed a map indicating areas of anomalous seismic activity in eastern and western Canada. The map predicted seismic activity between 2009 and 2014 for eastern Canada and between 2009 and 2018 for Western Canada.
The PI maps showed a cluster of anomalous activity appearing very close to where the Magnitude 5 earthquake happened near Ottawa in June 2010. Other such pockets appear close to Montreal and Quebec City.
The PI map for western Canada suggests areas for concern include inland of Vancouver, including Richmond and Delta, B.C., as well as north of Vancouver.