ESDS Program

Deploying Technology for Distributed Use of Global Navigation Satellite System Products in Earthquake and Tsunami Warning

Principal Investigator (PI): Yehuda Bock, University of California San Diego, Scripps Institution of Oceanography

Tsunamis occur when a large volume of ocean water is displaced by an earthquake, volcanic eruption, or landslide. A local tsunami is a tsunami that causes damage within a short distance of the tsunami-causing event (~100 km). Because of the close proximity, the first waves of these tsunamis reach the coastline in less than an hour, making these tsunamis especially deadly. An example is the March 11, 2011 tsunami generated by the Mw 9.0 Tohoku-oki earthquake, which resulted in over 18,000 casualties and extensive, long-term damage to infrastructure, including the Fukushima nuclear facility.

The best way to avoid casualties and loss of life is a tsunami early warning system. The National Oceanic and Atmospheric Administration’s (NOAA) previous systems used tsunami wave measurements to create basin-wide warnings. But these methods are not timely enough to warn of local tsunamis.

The project developed a prototype system for local tsunami warning using geodetic and seismogeodetic methods. This technology is being integrated into NOAA Tsunami Warning Centers (TWCs) in Alaska and Hawaii to improve their capabilities to issue local tsunami warnings.

Bock’s team at Scripps Institution of Oceanography worked with NOAA TWCs to generate evacuation warnings through a real-time seismic analysis program called GPS in Earthworm (GWORM). GWORM processes and analyzes Global Navigation Satellite Systems (GNSS) data combined with measurements from seismic instruments allowing real to near real-time products including rapid tsunami warning and modeling.

Read about the GWORM project at the Scripps Orbit and Permanent Array Center (SOPAC).


  • Goldberg, D., Bock, Y. (2017). Self-contained local broadband seismogeodetic early warning system: Detection and location. Journal of Geophysical Research Solid Earth, 122(4), 3197- 3220. doi:10.1002/2016JB013766
  • Goldberg, D. E., Melgar, D., Bock, Y., and Allen, R.M. (2018). Geodetic Observations of Weak Determinism in Rupture Evolution of Large Earthquakes. Journal of Geophysical Research, 123. doi:10.1029/2018JB015962.
  • Melgar, D., Allen, R. M., Riquelme, S., Geng, J., Bravo, F., Carlos Baez, J., Parra, H., Barrientos, S., Fang, P., Bock, Y., Bevis, M., Caccamise, D.J., Vigny, C., Moreno, M., and Smalley Jr., R. (2016). Local Tsunami Warnings: Perspectives from Recent Large Events. Geophysical Research Letters, 43, 1109–1117. doi:10.1002/2015GL067100
  • Melgar, D. and Bock, Y. (2015). Kinematic earthquake source inversion and tsunami inundation prediction with regional geophysical data. Journal of Geophysical Research Solid Earth, 120. doi:10.1002/2014JB011832
  • Ruhl C. J., Melgar, D., Geng, J., Goldberg, D.E., Crowell, B.W., Allen, R.M., Bock, Y., Barrientos, S., Riquelme, S., Baez, J.C., Cabral-Cano, E., Perez-Campos, X., Hill, E.M., Protti, M., Ganas, A., Ruiz, M., D’Anastassio, E., Kawamoto, S. (2018). A Global Database of Strong Motion Displacement GNSS Recordings and an Example Application to PGD Scaling, Seismological Research Letters, 90(1), 271-279. doi:10.1785/0220180177
  • Watanabe, S., Bock, Y., Melgar, D., and Tadokoro, K. (2018). Tsunami scenarios based on interseismic models along the Nankai Trough, Japan from seafloor and onshore geodesy. Journal of Geophysical Research Solid Earth, 123(3), 2448-2461. doi:10.1002/2017JB014799
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