During 2017, Oklahoma and southern Kansas experienced Mw 3+ earthquakes more frequently than in California. Although the annual count of earthquakes in the Oklahoma/Kansas area has declined since peaking in 2015, the rate of earthquake occurrence is still extremely high. More than 50 events (Mw 3+) have occurred since the start of 2018, including events of Mw 4.6 and Mw 4.5 during the first weeks of April, with shaking strong enough to be felt in Oklahoma City.
In Oklahoma and other parts of the Central and Eastern United States, research studies have linked the increased occurrence of earthquakes to oilfield wastewater injection. Damage has mostly been minimal, but the ground shaking occurring from events greater than or equal to Mw5 could have produced extensive damage had comparable events occurred in more greatly populated areas of the state.
In 2016, the United States Geological Survey (USGS) released their first short-term forecast for seismic hazard — this was meant to capture the increased (but potentially transient) nature of this hazard, and the forecast emphasized that the seismic hazard in Oklahoma is comparable to that of California. Since the first one-year forecast in 2016, the USGS has released subsequent forecasts for 2017 and now for 2018.
This blog is a reprint of an article published in Canadian Underwriter
New insights often challenge the established view. The view of earthquakes in Canada is changing, including shifts in the seismic risk within the greater Metro Vancouver area and in the balance of seismic risk between the east and west.
Starting with Metro Vancouver, insured seismic risk was previously viewed as being more heavily concentrated in the city proper, given the exposure concentration, including a prevalence of high-value buildings. But based on insights, the product of a new RMS model focused on earthquake risk in Canada, it appears insured seismic risk is driven more by exposure in the expansive region to the south of Vancouver, which straddles the main arm of the Fraser River.
Through our partnership with the Rockefeller Foundation’s 100 Resilient Cities initiative, RMS is tasked with helping cities around the world become more resilient to the physical, social, and economic challenges that are a growing part of the 21st century. Our recent engagement with the city of Berkeley, California highlighted how modeling can be used to help a city acutely understand its risk and create policy that accurately protects against it, thereby helping to save lives of vulnerable populations.
RMS completed a dual-view seismic analysis for the city of Berkeley. The first was a city-wide analysis showcasing the vulnerability of all neighborhoods across Berkeley under various magnitude scenarios. RMS then completed a building-level study on the city’s critical infrastructure of care and shelter sites. These structures are the city’s emergency shelters and are intended to house all displaced residents after an earthquake. Our analysis concluded that these shelters are located in areas susceptible to higher than average damage, indicating that these facilities would be critical to surrounding neighborhoods following an earthquake. Furthermore, we found that in their current construction state, these buildings performed worse than average in all seismic scenarios modeled and that retrofitting these buildings was an economical way to improve building performance.
This RMS analysis proved to be a key recommendation that Berkeley’s Chief Resiliency Officer took to the city council for a bond measure to fund retrofits for their care and shelter sites. If Berkeley secures the funding for these retrofits, our analysis will have provided leverage for a policy directive that will result in increased protection for particularly vulnerable segments of the population exposed to seismic risk.
RMS was able to showcase the seismic risk of all neighborhoods throughout the city, contextualize the geographic vulnerability of shelter sites, and propose measures for helping to ensure that these critical pieces of infrastructure help to protect the populations that they serve. This project highlights that catastrophe modeling can be a key determinant in helping governments, NGOs, and the private sector understand their risk and increase resilience.