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Latest Earthquake | Chat Share
Earthquake early warning (EEW) systems use earthquake science and the technology of monitoring systems to alert devices and people when shaking waves generated by an earthquake are expected to arrive at their location. The seconds to tens of seconds of advance warning can allow people and systems to take actions to protect life and property from destructive shaking.
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Earthquake early warning systems use earthquake science and the technology of monitoring systems to alert devices and people when shaking waves generated by an earthquake are expected to arrive at their location. The seconds to tens of seconds of advance warning can allow people and systems to take actions to protect life and property from destructive shaking.
Even a few seconds of warning can enable protective actions such as:
EEW systems are currently operating in several countries, and others are building them. Since 2006 the USGS has been working to develop EEW for the United States, with the help of several cooperating organizations including the California Geological Survey (CGS), the California Institute of Technology (Caltech), the California Office of Emergency Services (CalOES), the Moore Foundation, the University of California, Berkeley, the University of Washington, and the University of Oregon. The goal is to create and operate an EEW system for the highest risk areas of the United States beginning with the West Coast states: California, Washington, and Oregon.
A demonstration EEW system called ShakeAlert® began sending test notifications to selected users in California in January 2012. The system detects earthquakes using the California Integrated Seismic Network (CISN),an existing network of about 400 high-quality ground motion sensors. CISN is a partnership between the USGS, State of California, Caltech, and University of California, Berkeley, and is one of seven regional networks that make up the Advanced National Seismic System (ANSS).
In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert® early warning test system in California. This “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost. This next-generation system will not yet support public warnings but will allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert® warnings in areas with sufficient coverage. The USGS has published an Implementation Plan with the steps needed to complete the system and begin issuing public alerts.
Since 2008, the USGS Earthquake Hazards Program has supported research and development on earthquake early warning in partnership with Caltech, University of California Berkeley, and others, with goals to develop methods that would allow rapid detection of earthquakes in the western United States, to test and improve those methods using the California Integrated Seismic Network (CISN), to define the network improvements that would be needed to support a fully operational system, and to build a prototype system capable of providing early warnings to certain test users. Continued funding of and by the USGS complements funding from a private foundation recently awarded to the academic institutions (partners in the Advanced National Seismic System (ANSS) for research on and development of EEW components. This increase is part of an $8.6 million initiative to improve USGS disaster response capabilities through preparedness and robust monitoring.
The earthquake early warning system under development leverages federal and state investments already made in the ANSS that monitors earthquake activity in the US. By utilizing an existing, active seismic network, the early warning system can be tested and monitored daily through existing operations. Any infrastructure improvements required for EEW will also result in improved information for emergency response and aftershock forecasting. For instance, in 2011, upgrades to stations across California have been completed to reduce latencies in packaging and sending ground motion observations useful for EEW.
Earthquake Early Warning systems are operational in several countries around the world, including Mexico, Japan, Turkey, Romania, China, Italy, and Taiwan. All of these systems rapidly detect earthquakes and track their evolution to provide warnings of pending ground shaking. Systems can vary depending on the local faults and the specific ground motion data available.
Examples of Early Warning Systems
Mexico City has an EEW system that warns of strong shaking from large earthquakes that occur off of the country’s coast. The system consists of a series of sensors located along the coast that detect shaking from a large earthquake and rapidly determine the location and magnitude. Since Mexico City is located several hundred miles from the main plate boundary they can receive up to a minute or more of warning of the impending shaking for subduction zone earthquakes, but warning times are shorter for earthquakes that occur closer to the city. This system has been in operation since 1991.
Time to Detect an Event
An earthquake early warning system on the west coast of the United States could provide up to tens of seconds of warning prior to shaking arriving. The time required to detect and issue a warning for an earthquake is dependent on several factors:
Improving the sensor network
The most important component of an earthquake early warning system is a dense network of seismic and geodetic stations with robust communications. Future development of the warning system will include the installation of larger numbers of seismic stations and upgrading station telecommunications. The current seismic station densities in California are currently much lower than the Japanese public alert system. New sensors are needed in California to reduce earthquake detection times allowing warnings to be issued faster.
Additional Sources of Ground Motion Measurements
In the future, additional sources of ground motion observations can be integrated in the EEW algorithms. Additional data may be able to help reduce the time to detection and improve early estimates of earthquake magnitude and location.
Some examples include:
Every available technology will be used to ensure that EEW messages reach as many people and as quickly as possible. Most currently available mass messaging technologies are too slow for EEW. Unlike the Japanese system, here in the US we are unable to send messages to large numbers of cell phones without delays. However, many promising technologies are on the horizon like broadcast text messaging, smartphone apps and recent upgrades to the national Integrated Public Alert and Warning System (IPAWS). EEW may also open the door to many public/private partnerships.
Information on the ShakeAlert Product
The EEW system must be connected with users of the warning ahead of time, and therefore requires a public outreach effort upon implementation to make people aware of the system and how to respond to it. Responses are most effective when automated and pre-established so the recipients know what action to take when they get a warning.
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