David J. Wald

David birdwatching at sunset in Southern California

David J Wald (born May 6, 1962) is a Seismologist with the United States Geological Survey (USGS) at the National Earthquake Information Center (NEIC) in Golden, Colorado. He is an Adjunct Professor in Geophysics at the Colorado School of Mines. and was recently the Editor-in-Chief of the Earthquake Engineering Research Institute's (EERI) journal, Earthquake Spectra, from 2018-2022.

Wald is involved in the research, development, and operations of real-time information systems at the USGS National Earthquake Information Center. He has developed and manages products such as ShakeMap™, Did You Feel It?™, the community-science system, and is responsible for developing other systems for post-earthquake response and pre-earthquake mitigation, such as ShakeCast™ and PAGER.

Education and early career

Wald received his Bachelor's in Geology and Physics from St. Lawrence University in 1984. He then completed his Master's in Geophysics from the University of Arizona in 1986. He worked in Pasadena, California, for Woodward-Clyde Consultants from 1986-1988 on seismic hazard assessments for the Diable Canyon Nuclear Power Plant. David went on to California Institute of Technology (Caltech) in Pasadena, CA, and was awarded his Ph.D. in Geophysics in 1993. Wald then began working at the USGS in Pasadena, CA, in 1993 as a National Research Council Post-Doctoral Fellow and stayed on there as a researcher. He and his wife, Lisa Wald, also at the USGS, later transferred to the Golden, CO USGS office to work at the National Earthquake Information Center (NEIC).

Research and products

ShakeMap

A ShakeMap showing the Peak Ground Acceleration (PGA) of the 2023 Turkey earthquake.

The goal of ShakeMap was to "go beyond magnitude and epicenter” to depict the variations in the distribution of shaking intensity (Wald et al., 1999a). Here, “shaking intensity” is used informally, as in "How intense was the shaking?".

ShakeMap is now an open-source software program employed to automatically produce a suite of maps and products that portray the geographical extent and severity of potentially damaging shaking following an earthquake. ShakeMap is routinely used to provide post-earthquake situational awareness for emergency management and response and for damage and loss estimation. ShakeMap is also the primary shaking hazard input for many other downstream USGS earthquake products, including ShakeCast’s assessments of critical facilities, PAGER’s societal losses, and estimates of ground failure.

Did You Feel It?

Did You Feel It? civilian responses to 2023 Turkey earthquake.

For DYFI, Wald leveraged the work of Lori Dengler and Jim Dewey (Dengler & Dewey, 1998) following the Northridge earthquake. Their large volume of macroseismic phone surveys motivated them to create a “community decimal intensity” by assigning numerical values to individual questionnaire responses that they could calibrate against the Modified Mercalli Intensity (MMI) scale, the macroseismic intensity scale in use in the U.S. The numerical assignment of intensities from questionnaires lent itself naturally to automating the entire process of data collection, intensity assignment, and publishing via the internet, which today creates community-sourced maps of perceived intensity after an earthquake.

DYFI has been operating for over two decades (1999–2022) in the U.S. and nearly 18 years globally. The survey has collected over 6 million individual DYFI intensity reports during that period. DYFI allows for high rates and quantities of macroseismic data collection. High-quality MMI maps can be made almost immediately with complete coverage at a higher resolution than in the past.

ShakeCast

In and around 2000, via contacts with the Caltech ERA, Wald began interacting with many utility and lifeline operators. A common query was, "Given a ShakeMap, how can I tell what the level of shaking was at each of my facilities?” Working initially with Phil Naecker, an IT and infrastructure consultant, and with support from Loren Turner of the California Department of Transportation (Caltrans), David's team prototyped ShakeCast—short for ShakeMap Broadcast. ShakeCast was developed as a post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap to compare ground shaking intensity measures against a user’s facilities.

ShakeCast is now a fully automated software system for delivering specific ShakeMap products to critical users and triggering established post-earthquake response protocols. ShakeCast generates potential damage assessments and inspection priority notifications, maps, and web-based products for critical users, emergency managers, and anyone specified on a need-to-know basis.

PAGER - (Prompt Assessment of Global Earthquakes for Response)

Single page example of a PAGER automated response following the 2023 Turkey earthquake.

The primary purpose of the PAGER system is to inform emergency responders, government and aid agencies, and the media regarding the potential scope of the disaster. Earthquake alerts—formerly sent based on event magnitude and location or population exposure to shaking—are generated based on the estimated range of fatalities and economic losses.

PAGER is now an automated USGS system that generates information concerning the impact of significant earthquakes worldwide within approximately 20 minutes of any Magnitude>5.4 events. PAGER rapidly assesses earthquake impacts by combining data about populations exposed to estimated levels of shaking intensity with models of economic and fatality losses based on past earthquakes in each country or region of the world.

Awards

• 2004 - Incorporated Research Institutions for Seismology / Seismological Society of America’s Distinguished Lecturer
• 2009 - Awarded Seismological Society of America’s Frank Press Public Service Award
• 2014 - Earthquake Engineering Research Institute (EERI) Distinguished Lecturer
• 2016 - U.S. Department of the Interior Meritorious Service Award
• 2021 - American Geophysical Union Fellow
• 2021 - U.S. Geological Survey Shoemaker Lifetime Achievement Award in Communications
• 2022 - SSA and EERI's William B. Joyner Memorial Lecturer

Publications

Wald’s research and collaborations have resulted in more than 450 authored or co-authored professional publications, including journal papers, USGS publication series, conference papers, and published abstracts. His H-Index is 66, with over 20,000 total citations. Some recent (2020+) publications include:

• Heath, D. E., D.J. Wald, C.B. Worden, E.M. Thompson, and G.M. Smoczyk (2020). A global hybrid VS30 map with a topographic slope–based default and regional map insets, Earthquake Spectra, 36(3), 1570-1584.
• Langenbruch, C., W.L. Ellsworth, J.U. Woo, and D.J. Wald (2020). Value at induced risk: Injection‐induced seismic risk from low‐probability, high‐impact events, Geophy. Res. Lett. 47 (2), e2019GL085878.
• Noh, H., K.S. Jaiswal, D. Engler, and D.J. Wald (2020). An efficient Bayesian framework for updating PAGER loss estimates, Earthquake Spectra, 36(4), 1719-1742.
• Quitoriano, V., and D. J. Wald (2020). USGS “Did You Feel It?”—Science and lessons from twenty tears of community science-based macroseismology, Frontiers in Earth Sci. 8 (120).
• Wald, D. J., H.A. Seligson, et al. (2020). A domestic earthquake impact alert protocol based on the USGS PAGER and FEMA Hazus loss estimation systems, Earthquake Spectra 36 (1), 164-182.
• Wald, D. J., V. Quitoriano and O. Dully (2020). Emergency Service fills in Holes in USGS’s Rapid Post-Earthquake Intensity Reporting, Eos, 22 February 2021.
• Wald, D. J. (2020). Practical limitations of earthquake early warning, Earthquake Spectra.
• Wald, D. J. Worden, C. B., Thompson, E. M., and M. Hearne (2021). ShakeMap Operations, Procedures, and Policies, Earthquake Spectra.