2007 GSA Denver Annual Meeting (28–31 October 2007)

Paper No. 2
Presentation Time: 1:55 PM


WALD, David J., National Earthquake Information Center, U.S. Geological Survey, 1711 Illinois St, Golden, CO 80401, wald@usgs.gov

The U.S. Geological Survey's “Did You Feel It?” (DYFI) program is an automatic web-based system for rapidly generating seismic intensity maps based on shaking and damage reports collected from Internet users immediately following earthquakes. DYFI is a vast new source of seismological data that provides information about intensity distributions for earthquakes around the country and globe that would otherwise be difficult, if not impossible, to gather. Since 2000, more than 3/4 million responses have been compiled in the U.S. alone. DYFI benefits from several unique aspects of the nature of earthquakes. The vivid and often frightening nature of an individual's earthquake experience offers an opportune time to engage citizens in the process of contributing data to the USGS, while simultaneously affording a chance for the USGS to educate. School teachers in California have recognized this potential teachable moment and utilize DYFI in the classroom to help explain earthquakes. For the general public, sharing one's experience and knowing that the report serves a useful scientific purpose is essential in the participatory process. At higher intensity levels, DYFI further provides a form of catharsis, by writing extended first-person accounts that provide a release valve for the frightened while at the same time supplying a wealth of data on disaster response and risk perception. On the basis of these accounts, sociological studies indicate that repeat visitors have a better understanding of the nature of earthquakes having been inculcated to understand the difference between earthquake magnitude and intensity, a basic requirement for understanding of their own earthquake risk. Scientifically, DYFI data make up in quantity what they may lack in scientific quality, and help resolve long-standing issues in earthquake science. Such issues have been difficult to address due to the paucity of instrumental data in regions of low seismicity. DYFI data provide the strongest evidence that earthquakes produce more high-frequency energy in the central and eastern United States (CEUS) than in California and confirm lower attenuation of shaking with distance, resulting in stronger shaking over a wider area and thus more potential damage for CEUS earthquakes. DYFI can be found online at http://earthquake.usgs.gov/dyfi/.