Earthquake Early Warning
Development and Uses
Earthquake early warning (EEW) detects and measures earthquakes fast enough that warning can be given before the strongest shaking arrives, providing seconds to minutes to prepare.
Earthquake early warning is being implemented in many locations around the world. The 2011 Tohuku Earthquake demonstrated some of its advantages. The earthquake was recognized as serious within 30 seconds of its initiation offshore. Tokyo residents had ~30 seconds warning of approaching strong ground motion. Cell phone alarms warned millions of people when large aftershocks were likely to soon rattle them.
On the west coast of the the US, with USGS funding, Cal Tech and UC Berkeley have developed and are testing an early prototype EEW system known as ShakeAlert in California. In November, 2012, the Moore Foundation announced awarded grants to Cal Tech, UC Berkeley, and the University of Washington to develop and begin testing this prototype system. The USGS will help coordinate these activities.
ShakeAlert Beta Test
Video of the earthquake early warning system during the Tohoku Earthquake, March 11, 2011.
Nuts and Bolts
- Less destructive P waves travel faster than the more destructive S waves, and so will arrive first at any given location.
- A dense seismic station network near the earthquake source can quickly detect seismic waves well before the more significant shaking will arrive at more distant population centers.
- Data transmission to PNSN, processing at PNSN, and distribution to the end user is very fast relative to seismic travel times.
For specifics see USGS Fact Sheet 2014-3083.
EEW Costs and Benefits
A study prepared by the Pacific Earthquake Engineering Research Center (PEER) in the state of California explored the anticipated value of an earthquake early warning system through a series of interviews with organizations representing important sectors of the state's infrastructure and economy. The interviews focused on potential uses of EEW and perceived benefits to the public as well as their own empoyees and businesses.
Major points of the study were:
- The capital cost to construct and launch a California EEW system is estimated to be $28 million, and the personnel and operating expenses are estimated at $17 million annually.
- It was unanimously perceived that the overall societal benefits of a statewide EEW system is very high - a few seconds of advance warning could possibly help millions to Drop, Cover, and Hold On before heavy shaking begins, as well as increase public preparedness for earthquakes and reduce anxiety.
- Access and concrete use of an EEW system by different sectors of the state's infrastructure and economy could reduce organizational and economic disruptions, benefitting customers and communities by providing essential services related to safety, loss avoidance, and resumption of normal life.
- System reliability, design and development of delivery mechanisms, overcoming IT security and software issues, and appropriate training or edcuation of personnel must all be addressed before sectors can make full use of EEW.
- Obtaining secure and consistent funding, providing equal access for both organizations and society as a whole, a realistic timeframe for implementing EEW, establishing practical and appropriate methods of delivery, and public earthquake education and awareness must all be considered.
- Furthur study and technologic development is essential for launching a statewide EEW system in California and incorporating global standards.
For more detailed information, read the complete California Earthquake Early Warning System Benefit Study
UW's specific research objective is to develop the capability of issuing an alert tens of seconds after the onset of a large Cascadia Subduction Zone earthquake. The PNSN has hosted past workshops and will host another workshop in September 2016 at the University of Washington's Urban Horticulture Center reporting the progress of earthquake early warning and discussing beta testers for the system.
- September 2016 workshop
- February 2015 workshop
- February 2013 stakeholders workshop - Meeting notes from this innitial meeting were released in March 2013. Participants have begun conversations on how EEW system alerts might be integrated into operations and communications systems to reduce losses.
EEW in the News