Which Earthquake Accounts Matter?

Susan E. Hough

Published August 16, 2021, SCEC Contribution #11595, 2021 SCEC Annual Meeting Poster #004

In a recent study, Hough and Martin (2021) considered the extent to which socioeconomic factors influence the numbers and distribution of contributed reports available to characterize the effects of both historical and recent large earthquakes. I explore the question further, focusing on analysis of widely felt earthquakes near major population centers in northern and southern California since 2002. For earthquakes through 2014, there is a correlation between average household income in a postal ZIP code and the rate of responses to the U.S. Geological Survey “Did You Feel It” (DYFI) system. Visual inspection of results suggests that the correlation appears to be less pronounced since 2018, which might suggest that a DYFI digital divide is getting smaller over time. To explore results in more detail, I consider five earthquakes between 2011 and 2021 that generated relatively uniform shaking (typically intensity 3-4) across the greater Los Angeles region. For all of these events, response rate varies by two orders of magnitude across the region, with a clear correlation with demographics, and consistent spatial patterns in response rate for earthquakes 10 years apart. While there is no evidence that uneven DYFI participation in California impacts significantly the reliability of intensity data collected, the results reveal that DYFI participation is significantly higher in affluent parts of southern California compared to economically disadvantaged areas.

Key Words
community science

Hough, S. E. (2021, 08). Which Earthquake Accounts Matter?. Poster Presentation at 2021 SCEC Annual Meeting.

Related Projects & Working Groups
Communication, Education, and Outreach (CEO)