ShakeAlert

ShakeAlert
Name	ShakeAlert
Type	Seismic early warning system
Established	2018
Operator	United States Geological Survey; partner agencies
Area	Western United States
Status	Operational

ShakeAlert

ShakeAlert is a seismic early warning system designed to detect earthquakes and issue alerts seconds to minutes before significant ground shaking. It integrates networks of seismic sensors, real-time telemetry, and automated alert distribution to public agencies, private partners, and the public. The system is managed by the United States Geological Survey in collaboration with regional partners including the California Governor's Office of Emergency Services, the California Institute of Technology, and the University of Washington.

Overview

ShakeAlert provides automated notifications that aim to give users lead time to take protective actions prior to strong shaking from earthquakes such as the 1906 San Francisco earthquake, the 1989 Loma Prieta earthquake, and other notable events along the San Andreas Fault. The program links seismic arrays, real-time computing facilities, and dissemination channels used by entities like Caltrans, Bay Area Rapid Transit, Los Angeles County Metropolitan Transportation Authority, and private organizations including Google, Apple Inc., and Microsoft. Alerts may be distributed via mobile platforms, public sirens, transit control centers, and industrial control systems similar to those used by Southern California Edison and Pacific Gas and Electric Company.

History and Development

The conceptual roots trace to early warning research by institutions such as the US Geological Survey and academic groups at California Institute of Technology, University of California, Berkeley, and University of Washington. Pilot deployments were informed by historic earthquakes including the Northridge earthquake and studies following the Tohoku earthquake and tsunami. Legislative and funding milestones involved the National Earthquake Hazards Reduction Program and appropriations from the United States Congress. Partnerships expanded through agreements with state agencies like the Oregon Office of Emergency Management and municipal partners in Seattle and San Francisco.

Technology and Operation

ShakeAlert's architecture combines dense seismic networks (e.g., arrays maintained by Caltech, USGS, and the Pacific Northwest Seismic Network), real-time algorithms developed in collaboration with researchers at UC Berkeley and University of Washington, and distribution systems interfacing with platforms from Google and Apple Inc.. The system uses detection algorithms similar to those studied after the 2011 Tōhoku earthquake and tsunami and incorporates P-wave/S-wave discrimination techniques used by observatories like Menlo Park and Seattle Volcano Observatory. Operational decision-making involves coordination among the National Oceanic and Atmospheric Administration, state emergency management agencies, and transit operators such as Caltrain and Sound Transit.

Coverage and Deployment

Deployment began in California, expanded to the Pacific Northwest, and later included parts of Nevada and Oregon, covering seismic regions like the Cascadia Subduction Zone and the San Andreas Fault Zone. Coverage expansion involved collaboration with state governments of California, Oregon, and Washington and municipalities including Los Angeles, San Francisco, and Portland, Oregon. Integration into devices and services required coordination with technology companies such as Google, Apple Inc., Samsung Electronics, and telecom providers like AT&T and Verizon Communications for cell broadcast capability.

Effectiveness and Performance

Operational performance has been analyzed using case studies from earthquakes monitored by networks including the Southern California Seismic Network and the Pacific Northwest Seismic Network. Effectiveness metrics reference lead times achieved during events similar to the 2014 South Napa earthquake and modeled scenarios for the Cascadia earthquake and the San Andreas rupture scenarios studied by researchers at USC, Stanford University, and UC Berkeley. Independent evaluations involve institutions such as the National Academies of Sciences, Engineering, and Medicine and emergency planners from FEMA and state offices examining alert latency, false alarm rates, and actionable response rates.

Criticisms and Limitations

Critiques cite constraints identified by seismologists at UC Berkeley and Caltech regarding limited lead time for near-source ruptures on faults like the Hayward Fault and uncertainties in magnitude and location estimates for complex ruptures analogous to the 1992 Landers earthquake. Limitations in sensor density and telemetry in rural areas raise concerns noted by agencies in Nevada and Idaho, while integration challenges with private infrastructure have been highlighted by utilities such as Pacific Gas and Electric Company and transit operators. Policy and funding concerns have been raised in hearings before the United States Congress and analyses by the Government Accountability Office.

Future Developments and Research

Planned advancements include densification of seismic and GNSS instrumentation informed by work at Scripps Institution of Oceanography, algorithmic improvements from researchers at UC Santa Cruz and ETH Zurich collaborations, and enhanced interoperability with communications platforms from Google and Apple Inc.. Research priorities emphasize machine-learning approaches explored at MIT and Stanford University, integration with tsunami warning systems coordinated with NOAA, and expanded international collaboration with agencies like Japan Meteorological Agency and Natural Resources Canada. Ongoing demonstrations with state agencies and private partners aim to improve usability, reduce false alerts, and increase lead times for communities across regions including Northern California and the Pacific Northwest.

Category:Earthquake early warning systems