An earthquake warning system or earthquake early warning system is a system of

accelerometer An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is accele ...

seismometer A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu ...

s, communication, computers, and alarms that is devised for notifying adjoining regions of a substantial

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

while it is in progress. This is not the same as

earthquake prediction Earthquake prediction is a branch of the science of seismology concerned with the specification of the time, location, and magnitude of future earthquakes within stated limits, and particularly "the determination of parameters for the ''next'' s ...

, which is currently incapable of producing decisive event warnings.

Time lag and wave projection

An earthquake is caused by the release of stored elastic strain energy during rapid sliding along a fault. The sliding starts at some location and progresses away from the

hypocenter In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy s ...

in each direction along the fault surface. The speed of the progression of this fault tear is slower than, and distinct from the speed of the resultant

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

and

shear Shear may refer to: Textile production *Animal shearing, the collection of wool from various species **Sheep shearing *The removal of nap during wool cloth production Science and technology Engineering *Shear strength (soil), the shear strength ...

waves, with the pressure wave traveling faster than the shear wave. The pressure waves generate an abrupt shock. The shear waves generate periodic motion (at about 1 Hz) that is the most destructive to structures, particularly buildings that have a similar resonant period. Typically, these buildings are around eight floors in height. These waves will be strongest at the ends of the slippage, and may project destructive waves well beyond the fault failure. The intensity of such remote effects are highly dependent upon local soils conditions within the region and these effects are considered in constructing a

model A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...

of the region that determines appropriate responses to specific events.

Transit safety

Such systems are currently implemented to determine appropriate real-time response to an event by the train operator in urban rail systems such as

BART Bart is a masculine given name, usually a diminutive of Bartholomew, sometimes of Barton, Bartolomeo, etc. Bart is a Dutch and Ashkenazi Jewish surname, and derives from the name ''Bartholomäus'', a German form of the biblical name ''Barthol ...

(Bay Area Rapid Transit) and LA Metro. The appropriate response is dependent on the warning time, the local right-of-way conditions and the current speed of the train. Warning time Nepal Earthquake

Deployment

As of 2016,

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

and

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

have comprehensive, nationwide earthquake early warning systems. Other countries and regions have limited deployment of earthquake warning systems, including

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

(the

Mexican Seismic Alert System The Mexican Seismic Alert System (Spanish: ''Sistema de Alerta Sísmica Mexicano'' or SASMEX) is the earthquake warning system covering portions of central and southern Mexico. It currently provides up to 60 seconds' warning of earthquakes to Me ...

covers areas of central and southern Mexico including

Mexico City Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital and largest city of Mexico, and the most populous city in North America. One of the world's alpha cities, it is located in the Valley o ...

and

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...

), limited regions of

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

( the Basarab bridge in Bucharest), and parts of the United States. The earliest automated earthquake pre-detection systems were installed in the 1990s; for instance, in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, the Calistoga fire station's system which automatically triggers a citywide siren to alert the entire area's residents of an earthquake. Some California fire departments use their warning systems to automatically open

overhead door A garage door is a large door on a garage that opens either manually or by an electric motor (a garage door opener). Garage doors are frequently large enough to accommodate automobiles and other vehicles. Small garage doors may be made in a si ...

s of fire stations before the earthquake can disable them. While many of these efforts are governmental, several private companies also manufacture earthquake early warning systems to protect infrastructure such as elevators, gas lines and fire stations.

Canada

In 2009, an early warning system called

ShakeAlarm ShakeAlarm is an on-site earthquake early warning system (EEWS) developed by Weir-Jones Engineering Consultants in Vancouver, British Columbia. The system functions by detecting and identifying fast moving P-waves that arrive before the slower an ...

was installed and commissioned in

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. It was placed to protect a piece of critical transportation infrastructure called the

George Massey Tunnel The George Massey Tunnel (often referred to as the Massey Tunnel) is a highway traffic tunnel in the Metro Vancouver region of southwestern British Columbia. It is located approximately south of the city centre of Vancouver, British Columbia, ...

, which connects the north and south banks of the

Fraser River The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of Vancouver. The river's annual d ...

. In this application the system automatically closes the gates at the tunnel entrances if there is a dangerous seismic event inbound. The success and the reliability of the system was such that as of 2015 there have been several additional installations on the west coast of Canada and the United States, and there are more being planned.

Japan

Japan's Earthquake Early Warning system was put to practical use in 2006. The system that warns the general public was installed on October 1, 2007. Retrieved on 2008-06-29. It was modeled partly on the Urgent Earthquake Detection and Alarm System (UrEDAS) of

Japan Railways The Japan Railways Group, more commonly known as the or simply JR, consists of seven for-profit stock companies that took over most of the assets and operations of the government-owned Japanese National Railways (JNR) on April 1, 1987. Mo ...

, which was designed to enable automatic braking of

bullet train Bullet train may refer to: Rail * Shinkansen high-speed trains of Japan, nicknamed for their appearance and speed * Other high-speed trains of a similar appearance to Japanese trains * An ongoing project to build high-speed rail in India. Rail to ...

Gravimetric Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of a gravitational field or the properties of matter responsible for its creation are of interest. Units of measurement G ...

data from the 2011 Tōhoku earthquake has been used to create a model for increased warning time compared to seismic models, as gravity fields travel at the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ...

, much faster than seismic waves.

Mexico

The

, otherwise known as SASMEX, began operations in 1991 and began publicly issuing alerts in 1993. It is funded by the Mexico City government, with financial contributions from several states that receive the alert. Initially serving

with twelve sensors, the system now has 97 sensors and is designed to protect life and property in several central and southern Mexican states.

United States

The

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

(USGS) began research and development of an early warning system for the

West Coast of the United States The West Coast of the United States, also known as the Pacific Coast, Pacific states, and the western seaboard, is the coastline along which the Western United States meets the North Pacific Ocean. The term typically refers to the contiguous U.S ...

in August 2006, and the system became demonstrable in August 2009. Following various developmental phases, version 2.0 went live during the fall of 2018, allowing the "sufficiently functional and tested" system to begin Phase 1 of alerting California,

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. Even though ShakeAlert could alert the public beginning September 28, 2018, the messages themselves could not be distributed until the various private and public distribution partners had completed mobile apps and made changes to various emergency alerting systems. The first publicly available alerting system was the ShakeAlertLA app, released on New Year's Eve 2018 (although it only alerted for shaking in the

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

area). On October 17, 2019, Cal OES announced a statewide rollout of the alert distribution system in California, using

mobile app A mobile application or app is a computer program or software application designed to run on a mobile device such as a phone, tablet, or watch. Mobile applications often stand in contrast to desktop applications which are designed to run on d ...

s and the

Wireless Emergency Alerts Wireless Emergency Alerts (WEA, formerly known as the Commercial Mobile Alert System (CMAS), and prior to that as the Personal Localized Alerting Network (PLAN)), is an alerting network in the United States designed to disseminate emergency alert ...

(WEA) system. California refers to their system as the California Earthquake Early Warning System. A statewide alert distribution system was rolled out in Oregon on March 11, 2021 and in Washington on May 4, 2021, completing the alert system for the West Coast.

Global systems

Earthquake Network

In January 2013, Francesco Finazzi of the

University of Bergamo The University of Bergamo ( it, Università degli Studi di Bergamo; acronym: UniBG) is an Italian public university located in Bergamo, Italy. It was founded on 11 December 1968 and is organized in seven departments, three campuses and forty-one ...

started the

Earthquake Network Earthquake Network research project that aims to develop and maintain a crowdsourced smartphone-based earthquake warning system at a global level. The system uses the on-board accelerometers in privately-owned smartphones of volunteer participant ...

research project which aims at developing and maintaining a

crowdsourced Crowdsourcing involves a large group of dispersed participants contributing or producing goods or services—including ideas, votes, micro-tasks, and finances—for payment or as volunteers. Contemporary crowdsourcing often involves digita ...

earthquake warning system based on smartphone networks. Smartphones are used to detect the ground shaking induced by an earthquake and a warning is issued as soon as an earthquake is detected. People living at a further distance from the epicenter and the detection point may be alerted before they are reached by the damaging waves of the earthquake. People can take part in the project by installing the Android application "Earthquake Network" on their smart phones. The app requires the phone to receive the alerts.

MyShake

In February 2016, the

Berkeley Seismological Laboratory The Berkeley Seismological Laboratory (BSL) is a research lab at the Department of Geology at the University of California, Berkeley. It was created from the Berkeley Seismographic Stations, a site on the Berkeley campus where Worldwide Standard S ...

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

(UC Berkeley) released the MyShake mobile app. The app uses

s in phones that are stationary and connected to a power supply to record shaking and relay that information back to the laboratory. The system issues automated warnings of earthquakes of magnitude 4.5 or greater. UC Berkeley released a Japanese-language version of the app in May 2016. By December 2016, the app had captured nearly 400 earthquakes worldwide.

Android Earthquake Alerts System

On August 11, 2020,

Google Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...

announced that its

Android operating system Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Android is developed by a consortium of deve ...

would begin using accelerometers in devices to detect earthquakes (and send the data to the company's "earthquake detection server"). As millions of phones operate on Android, this may result in the world's largest earthquake detection network. Initially, the system only collected earthquake data and did not issue alerts (except for on the West Coast of the United States, where it provided alerts issued by the USGS's ShakeAlert system and not from Google's own detection system). Data collected by Android devices was only used to provide fast information on the earthquake via

Google Search Google Search (also known simply as Google) is a search engine provided by Google. Handling more than 3.5 billion searches per day, it has a 92% share of the global search engine market. It is also the most-visited website in the world. The ...

, although it was always planned to issue alerts for many other areas based on Google's detection capabilities in the future. On April 28, 2021, Google announced the rollout of the alert system to

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, the first countries to receive alerts based on Google's own detection capabilities. Google's alerts were extended to

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

Kyrgyz Republic Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the east ...

Tajikistan Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...

Turkmenistan Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the sout ...

and

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...

in June 2021.

OpenEEW

On August 11, 2020,

Linux Foundation The Linux Foundation (LF) is a non-profit technology consortium founded in 2000 as a merger between Open Source Development Labs and the Free Standards Group to standardize Linux, support its growth, and promote its commercial adoption. Additi ...

, IBM and Grillo announced the first fully open-source earthquake early-warning system, featuring instructions for a low-cost seismometer, cloud-hosted detection system, dashboard and mobile app. This project is supported by

USAID The United States Agency for International Development (USAID) is an independent agency of the U.S. federal government that is primarily responsible for administering civilian foreign aid and development assistance. With a budget of over $27 bi ...

, the

Clinton Foundation The Clinton Foundation (founded in 2001 as the William J. Clinton Presidential Foundation, and renamed in 2013 as the Bill, Hillary & Chelsea Clinton Foundation) is a nonprofit organization under section 501(c)(3) of the U.S. tax code. It was e ...

and

Arrow Electronics Arrow Electronics is an American ''Fortune'' 500 company headquartered in Centennial, Colorado. The company specializes in distribution and value added services relating to electronic components and computer products. The company was ranked ...

. Smartphone-based earthquake early-warning systems are dependent on a dense network of users near the earthquake rupture zone, whereas OpenEEW has focused instead on providing affordable devices that can be deployed in remote regions close to where earthquakes can begin. All components of this system are open source and available on the project's

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continuous ...

repositories.

Social media

Social networking sites such as Twitter and Facebook play a significant role during natural disasters. The United States Geological Survey (

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...

) has investigated collaboration with the social networking site

Twitter Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and interact with 280-character-long messages known as "tweets". Registered users can post, like, and ...

to allow for more rapid construction of ShakeMaps.Mahalia Miller, Lynne Burks, and Reza Bosagh Zade
Rapid Estimate of Ground Shaking Intensity by Combining Simple Earthquake Characteristics with Tweets
Tenth U.S. National Conference on Earthquake Engineering

References

External links

{{commons
Earthquake Early Warning
– California Institute of Technology
Bayesian Networks for Earthquake Magnitude Classification in a Early Warning SystemEarthquake Network
- The Earthquake Network project website
Earthquake Early Warning for Developing Countries
- Grillo website
An Open Source Earthquake Early Warning System
- OpenEEW website Earthquake and seismic risk mitigation