USGS ‘Did you feel it?

Interaction Type public -> government
Trigger Event Paucity of instrumental ground-motion data in regions of low seismicity (Atkinson and Wald, 2007).
Domain Provision of ground-motion data to US Geological Survey Community Internet Intensity Map for public information about earthquake activity
Organisation United States Geological Survey Community Internet Intensity Map (Did you feel it?) DYFI
Actors U.S. Geological Survey Earthquake Hazards Program
Data sets in use Various products are developed by the USGS from the DYDI data and other earthquake sensing and monitoring programs.
Process Citizens, upon feeling earthquake activity, must logon to the DYFI website and submit their observation. The intensity of the earthquake they have just felt is quantified using the Modified Mercalli Intensity (MMI) scale is used. There is no need for the citizen to have experience in seismology. Maps and graphics are generated automatically by the DYFI system and made available to the public.
Feedback There is no specific personalised feedback to the citizen contributor. Their submission is acknowledged and they can provide contact details in the input form.
Goal Outreach to citizens to become part of the seismic monitoring network and to allow the USGS to continue to learn and understand more about earthquake activity.
Side effects The data collected from DYFI is made compatible with ShakeMap: ShakeMap is a product of the U.S. Geological Survey Earthquake Hazards Program in conjunction with regional seismic network operators.
Contact Point

The US Geological Survey’s Community Internet Intensity Map (more commonly referred to as ‘Did you feel it?’) is a website that automatically maps reports from citizens about their perception of recent seismic activity in their areas. If a citizen feels a tremor of an earthquake these people can visit the DYFI website and report their location and their estimate of the intensity of the tremors they have just felt. In combination to a large network of sensors which are placed all over the world these additional citizen reports allow USGS to develop a more detailed map of the intensity of an earthquake’s activity. Over 360,000 earthquake events have been submitted to DYFI and are available to browse online on the archive section of the website. There is an option citizens to give first-person descriptions of how the earthquake affected them. However it is made clear on the form that if the USGS use this qualitative information the citizen will only be referred to as “the observer”. Contributors can watch the DYFI webpage for the display of their report. Maps and graphics are generated automatically by the DYFI system and made available to the public.

The Google Maps web interface to 'Did You Feel It?'
The Google Maps web interface to ‘Did You Feel It?’

The ‘Did you feel it?’ form interface is easy to use. Ideally citizens reporting earthquake events in the United States will know their ZIP code. Citizens from outside the USA can submit observations with their coordinates in longitude latitude. The form is mostly drop-down list based asking for feedback on: Your situation when the earthquake occurred, Your experience of the earthquake (shaking strength, duration, reaction), earthquake effects (sounds, damage to free standing objects, etc), damage to buildings, etc. Because DYFI appeals to people in this way the DYFI data make up in quantity what they may lack in scientific quality and offer the potential to resolve longstanding issues in earthquake ground-motion science. Such issues have been difficult to address due to the paucity of instrumental ground-motion data in regions of low seismicity (Atkinson and Wald, 2007). Prior to this system, intensity maps were rarely made for U.S. earthquakes of magnitude less than about 5.5; now intensities as low as magnitude 2.0. are routinely reported for the smallest felt earthquakes nationwide (Atkinson and Wald, 2007). Upon feeling earthquake activity, must logon to the DYFI website and submit their observation. The intensity of the earthquake they have just felt is quantified using the Modified Mercalli Intensity (MMI) scale is used. MMI measures the intensity of ground motions from the perspective of human and structural response on a qualitative scale from 1 (not felt) to 10 (very heavy damage) or sometimes 12 (total destruction), based on descriptions such as “felt indoors” (MMI = 3) to “felt by all, windows, dishes, glassware broken, weak plaster cracked” (MMI = 6) to “some structures with complete collapse” (MMI = 9). The MMI allows anyone to report activity. There is no need for the citizen to have experience in seismology. This citizen reporting allows the USGS to continue to learn and understand more about earthquake activity. In addition the USGS can then use this knowledge to inform emergency response planning efforts and budgets for modelling disaster relief (Brabham, 2013).

The vast amount of new data on earthquake ground motions and effects being collected from online citizen responses with the DYFI program offers a valuable new data resource for both qualitative and quantitative earthquake studies and has the potential to address some longstanding controversies in earthquake science. There are some negative aspects to ‘Did you feel it?’. Despite their significant value to emergency responders, the subjective observations of untrained citizens are only a qualitative indicator of the effects of an earthquake. Moreover, the effectiveness of DYFI based maps may be greatly hampered by the speed at which people report critical information during crises.

Main Lessons

  • QA/QC: The website application filters out erroneous responses the website states that the best filter is to have multiple responses per zip code to give a reliable average of the shaking over the area. “The wisdom of the crowd usually outweighs individual eccentricities”. The USGS reserve the right to manually exclude any responses they deem inappropriate or unnaturally high.
  • For rapid response to earthquakes  zip codes are preferable as the locational information provided. The DYFI website states that almost everyone knows immediately which zip code they are in, whereas few people know their latitude and longitude (and especially not to the needed precision that DYFI requires). They estimate that approximately 5-10% of respondents do not leave their address and there are correspondingly fewer responses on a geocode map vs. a zip code map.
  • The input form is very easy to use and avoids use of seismology terminology.
  • Atkinson and Wald (2007) indicate that the data collected from DYFI are very valuable. Their analyses of the DYFI data show this data as being extremely useful for rapid post-earthquake information and “they are also robust and of surprisingly high utility”. The data collected offers the potential to not only describe ground-motion effects qualitatively but to be used in quantitative scientific studies. The authors state that “the key to the usefulness of the data is simply this: they make up in quantity what they may lack in quality. Because there are so many responses, stable statistics on average effects are produced, illuminating ground-motion trends and allowing effective correlation and calibration with more-quantitative ground-motion measures”.

Reference Materials

Atkinson, G. M., and D. J. Wald (2007) “Did You Feel It?” intensity data: A surprisingly good measure of earthquake ground motion  Seism. Res. Lett. 78, 362-368

Brabham, D., 2013. Using Crowdsourcing in Government, Collaboration Across Boundaries. IBM Center for The Business of Government.

 

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