{"id":4652,"date":"2025-09-08T12:34:22","date_gmt":"2025-09-08T19:34:22","guid":{"rendered":"https:\/\/tungsten2.gps.caltech.edu\/?page_id=4652"},"modified":"2025-09-10T14:08:58","modified_gmt":"2025-09-10T21:08:58","slug":"shakealert-earthquake-early-warning-system","status":"publish","type":"page","link":"https:\/\/www.scsn.org\/index.php\/partnerships-resources\/shakealert-earthquake-early-warning-system\/","title":{"rendered":"Earthquake Early Warning system"},"content":{"rendered":"<p><!-- EEW Landing (polished) --><\/p>\n<style>\n  \/* Layout & type *\/\n  .eew-landing { max-width: 980px; margin: 0 auto; padding: 1rem 1.25rem 2rem; }\n  .eew-landing h1, .eew-landing h2, .eew-landing h3, .eew-landing h4 { line-height: 1.2; margin: 0.2em 0 0.5em; }\n  .eew-landing h2 { font-size: clamp(1.6rem, 2.4vw + 1rem, 2.2rem); text-align: center; }\n  .eew-landing p { margin: 0.6em 0 0.9em; }\n  .eew-landing .subtle { color: #444; }\n  .eew-landing .center { text-align: center; }<\/p>\n<p>  \/* Hero image *\/\n  .eew-hero { margin: 1rem auto 1.25rem; text-align: center; }\n  .eew-hero img { display: block; margin: 0 auto; width: 100%; max-width: 900px; height: auto; border-radius: 6px; }<\/p>\n<p>  \/* Card-ish details sections *\/\n  .eew-accordion details { \n    background: #fafafa; \n    border: 1px solid #e6e6e6; \n    border-radius: 10px; \n    margin: 0.75rem 0; \n    padding: 0.25rem 0.75rem 0.5rem;\n  }\n  .eew-accordion details[open] { background: #f7fbff; border-color: #d9ecff; }\n  .eew-accordion summary { \n    list-style: none; \n    cursor: pointer; \n    padding: 0.6rem 0.25rem; \n    outline: none;\n  }\n  \/* Hide native marker *\/\n  .eew-accordion summary::-webkit-details-marker { display: none; }\n  .eew-accordion summary::marker { content: none; }<\/p>\n<p>  \/* Custom caret *\/\n  .eew-accordion summary .caret {\n    display: inline-block; \n    width: 1em; \n    text-align: center; \n    margin-right: 0.35em; \n    transform: translateY(-1px);\n  }\n  .eew-accordion details:not([open]) summary .caret::before { content: \"\u25b8\"; }\n  .eew-accordion details[open] summary .caret::before { content: \"\u25be\"; }<\/p>\n<p>  \/* Summary title link (phrasing content only) *\/\n  .eew-accordion summary a { text-decoration: none; font-weight: 700; }\n  .eew-accordion summary a:hover, .eew-accordion summary a:focus { text-decoration: underline; }<\/p>\n<p>  \/* Lists inside details *\/\n  .eew-accordion ul { \n    margin: 0.25rem 0 0.5rem 1.25rem; \n    padding-left: 0.25rem; \n  }\n  \/* Optional: remove bullets at top level, keep for nested *\/\n  .eew-accordion > details > ul { list-style: none; margin-left: 0.25rem; }\n  .eew-accordion > details > ul > li { margin: 0.25rem 0; }\n  .eew-accordion > details > ul > li > ul { list-style: disc; margin-top: 0.25rem; }<\/p>\n<p>  \/* Footer note *\/\n  .eew-funding { \n    margin-top: 1.25rem; \n    padding: 0.75rem 1rem; \n    background: #fafafa; \n    border: 1px solid #eee; \n    border-radius: 8px; \n    font-size: 0.95em;\n  }\n<\/style>\n<div class=\"eew-landing\">\n<h2>ShakeAlert<sup>\u00ae<\/sup> Earthquake Early Warning System<br \/>for the West Coast of the United States<\/h2>\n<div class=\"eew-hero\">\n    <img decoding=\"async\" \n      src=\"https:\/\/www.scsn.org\/wp-content\/uploads\/EarlyWarning_Diagram_scsn.png\" \n      alt=\"Diagram illustrating how ShakeAlert earthquake early warning provides alerts before strong shaking arrives\">\n  <\/div>\n<p>Earthquake early warning (EEW) systems aim to quickly detect earthquakes and alert locations expected to experience significant shaking before the shaking arrives, potentially saving lives and preventing injuries. There are many EEW systems in operation and in development around the world, and the EEW system that is availablein the U.S. West Coast states of California, Oregon, and Washington is called the <strong>ShakeAlert<\/strong> system.<\/p>\n<p class=\"subtle\">The ShakeAlert system is operated by the U.S. Geological Survey (USGS) and is a cooperative project between the USGS, state agencies,and university partners including the California Institute of Technology (Caltech), the University of California, Berkeley (UC&nbsp;Berkeley),the University of Washington (UW), and the University of Oregon (UO).<\/p>\n<p><strong>This site focuses on contributions by the SCSN and Caltech Seismological Laboratory<\/strong>, and serves as a repository of resources for partners and the public. <\/p>\n<p><em>Expand the sections below<\/em> to view summaries and link to additional pages with in-depth information and resources.<\/p>\n<div class=\"eew-accordion\">\n<p>    <!-- Section 1 --><\/p>\n<details>\n<summary><span class=\"caret\" aria-hidden=\"true\"><\/span><a href=\"https:\/\/www.scsn.org\/?page_id=5291\">How does the ShakeAlert EEW System work?<\/a><\/summary>\n<ul>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5291\">General overview of how Earthquake Early Warning (EEW) operates and why it is <strong>not<\/strong> earthquake prediction.<\/a><\/li>\n<\/ul>\n<\/details>\n<p>    <!-- Section 2 --><\/p>\n<details>\n<summary><span class=\"caret\" aria-hidden=\"true\"><\/span><a href=\"https:\/\/www.scsn.org\/?page_id=5298\">How is EEW used? (How can I sign up for EEW?)<\/a><\/summary>\n<ul>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5298#how-can-i-benefit-from-the-shakealert-eew-system\">How can I benefit from the ShakeAlert EEW System?<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5298#how-can-i-get-shakealert-eew-on-my-phone\">How can I get ShakeAlert EEW on my phone?<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5298#what-are-the-common-alert-thresholds-used-in-shakealert\">What are the common alert thresholds used in ShakeAlert?<\/a><\/li>\n<\/ul>\n<\/details>\n<p>    <!-- Section 3 --><\/p>\n<details>\n<summary><span class=\"caret\" aria-hidden=\"true\"><\/span><a href=\"https:\/\/www.scsn.org\/?page_id=5309\">Overview of EEW algorithms and EEW operations at Caltech<\/a><\/summary>\n<ul>\n<li>\n          <a href=\"https:\/\/www.scsn.org\/?page_id=5309#shakealert-eew-operations-at-caltech\">ShakeAlert EEW Operations at Caltech<\/a>\n        <\/li>\n<li>\n          <a href=\"https:\/\/www.scsn.org\/?page_id=5309#eew-algorithms-in-current-shakealert-operations\">EEW Algorithms in Current ShakeAlert Operations<\/a><\/p>\n<ul>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#epic\">EPIC (Earthquake Point-source Integration Code)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#finder\">FinDer (Finite-fault Rupture Detector)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#g-fast\">G-FAST (Geodetic First Approximation of Size and Time)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#solution-aggregator\">Solution Aggregator<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#eqinfo2gm\">eqInfo2GM (Earthquake Information to Ground Motion)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#decision-module\">Decision Module<\/a><\/li>\n<\/ul>\n<\/li>\n<li>\n          <a href=\"https:\/\/www.scsn.org\/?page_id=5309#eew-algorithms-in-development-for-potential-future-shakealert-operations\">EEW Algorithms in Development for Potential Future ShakeAlert Operations<\/a><\/p>\n<ul>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#plum\">PLUM (Propagation of Local Undamped Motion)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5309#gma\">Ground Motion Aggregator (GMA)<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/details>\n<p>    <!-- Section 4 --><\/p>\n<style> li::marker { content: none; } <\/style>\n<details>\n<summary><span class=\"caret\" aria-hidden=\"true\"><\/span><a href=\"https:\/\/www.scsn.org\/?page_id=5334\">Overview of EEW Research and Development at Caltech<\/a><\/summary>\n<ul>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#finder-improvements\">Improving the FinDer EEW algorithm<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#plum-apples\">Improving the PLUM EEW algorithm (the APPLES configuration)<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#ground-motion-modeling\">Improving ground-motion modeling in EEW<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#das-eew\">Investigating using fiber-optic DAS in EEW applications<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#eew-visualization-performance-strategies\">Developing EEW performance visualization tools, performance evaluation methods, and preferred alerting strategies<\/a><\/li>\n<li><a href=\"https:\/\/www.scsn.org\/?page_id=5334#station-network-improvements\">Investigating station and network improvements<\/a><\/li>\n<\/ul>\n<\/details>\n<p>    <!-- Section 5 (placeholder\u2014left empty but styled) --> <\/p>\n<details>\n<summary><span class=\"caret\" aria-hidden=\"true\"><\/span><a href=\"https:\/\/www.scsn.org\/index.php\/partnerships-resources\/shakealert-earthquake-early-warning-system\/caltech-eew-team-members\/\">Caltech EEW team members<\/a><\/summary>\n<\/details><\/div>\n<p><\/br><\/p>\n<h5>How did this all start?<\/h5>\n<p>While there had been interest and some early research conducted at Caltech pertaining to earthquake early warning as far back as the 1980&#8217;s, those efforts weren&#8217;t combined and formalized until the 2000&#8217;s. Scientists and engineers at the California Institute of Technology (Caltech), USGS Pasadena, UC Berkeley, the Swiss Federal Institute of Technology (ETH), and the University of Southern California (USC\/SCEC) started working on earthquake early warning (EEW) research for California in 2007. This included the development and implementation of an early demonstration EEW system for California, called &#8220;CISN ShakeAlert&#8221; (Boese et al., 2012). The early ShakeAlert made use of the existing infrastructure of the <a href=\"http:\/\/www.cisn.org\">California Integrated Seismic Network<\/a> (CISN, Caltech\/UC Berkeley\/USGS), including real-time waveform data streams from at the time ~380 broadband and strong-motion stations throughout California. Now data streams from more than 1100 stations between California, Oregon, and Washington are being ingested by ShakeAlert to support the ShakeAlert Earthquake Early Warning System on the entire west coast of the US.<\/p>\n<p>Initially, the project was funded through the US Geological Survey (USGS) that also has the formal responsibility of earthquake alerting in the US. In early 2012, the <a href=\"http:\/\/www.moore.org\/\">Gordon and Betty Moore Foundation<\/a> provided three years of new funding for EEW research and development for the west coast of the US. Caltech, UC Berkeley, University of Washington, and USGS used these funds to accelerate EEW research and to improve the ShakeAlert system. In particular, the Moore funding enabled the research and development of new algorithms for creating more accurate warnings for finite-source large (M>7) earthquakes as well as enabling work with early-adopters of ShakeAlert and development of probability-based smart engineering applications. With the USGS spearheading the implementation and management of the ShakeAlert Earthquake Early Warning System, research continues at the Caltech Seismo Lab and other partner institutions to constantly improve warning times, accuracy, and the reliability of the system.<\/p>\n<p><\/br><\/p>\n<div class=\"eew-funding center\">Caltech receives funding from the USGS and the <a href=\"https:\/\/www.caloes.ca.gov\/office-of-the-director\/operations\/planning-preparedness-prevention\/seismic-hazards\/california-earthquake-early-warning-program\/\" rel=\"noopener noreferrer\" target=\"_blank\">California Office of Emergency Services (CalOES)<\/a> to help operate the ShakeAlert system and bring new innovations to the system.<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>ShakeAlert\u00ae Earthquake Early Warning Systemfor the West Coast of the United States Earthquake early warning (EEW) systems aim to quickly detect earthquakes and alert locations expected to experience significant shaking before the shaking arrives, potentially saving lives and preventing injuries.<span class=\"ellipsis\">&hellip;<\/span><\/p>\n<div class=\"read-more\"><a href=\"https:\/\/www.scsn.org\/index.php\/partnerships-resources\/shakealert-earthquake-early-warning-system\/\">Read more &#8250;<\/a><\/div>\n<p><!-- end of .read-more --><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":43,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"responsive\/full-width-page.php","meta":{"footnotes":""},"class_list":["post-4652","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/pages\/4652","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/comments?post=4652"}],"version-history":[{"count":109,"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/pages\/4652\/revisions"}],"predecessor-version":[{"id":5375,"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/pages\/4652\/revisions\/5375"}],"up":[{"embeddable":true,"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/pages\/43"}],"wp:attachment":[{"href":"https:\/\/www.scsn.org\/index.php\/wp-json\/wp\/v2\/media?parent=4652"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}