On March 28, Myanmar was rocked by a 7.8 magnitude earthquake that claimed over 5,000 lives and caused damage even in neighboring countries.<\/p>\n
In a study published July 10 in The Seismic Record<\/a>, seismologists confirmed previous research indicating that the southern part of the large earthquake\u2019s rupture, or fracture, took place at astounding speeds of up to between 3.1 and 3.7 miles per second (5 to 6 kilometers per second)\u2014at supershear velocity. This likely played a role in the earthquake\u2019s devastating impact.<\/p>\n When an earthquake strikes, the first seismic waves<\/a> to propagate from the epicenter are P waves, fast-moving waves that compress their way through all kinds of material but do not cause a lot of damage. Then come the S waves, or shear waves, which are slower but cause highly destructive perpendicular motion. Simply put, when parts of an earthquake\u2019s fault rupture at supershear velocity, it means that the speed of the break along a particular stretch of the rupture was faster than the speed of its S waves. In moderate earthquakes, rupture velocities are usually between<\/a> 50 and 85% of S-wave velocity.<\/p>\n Myanmar\u2019s earthquake occurred along the Sagaing Fault, which runs north-south through Myanmar. The fault is strike-slip, meaning two tectonic plates slide horizontally against each other. The Sagaing Fault\u2019s strike-slip movement in March was clearly captured in potentially first-of-its-kind footage<\/a> showcasing an expanse of land suddenly moving forward relative to the viewer.<\/p>\n<\/p>\n The natural disaster saw around 298.3 miles (480 km) of the Sagaing Fault rupture or \u201cslip,\u201d which is extremely long for a strike-slip rupture of this magnitude, according to the seismologists. By studying seismic and satellite imagery, they determined that the rupture had \u201clarge slip of up to 7 m [23 feet] extending \u223c85 km [52.8 miles] north of the epicenter near Mandalay, with patchy slip of 1\u20136 m [3.3\u201319.7 feet] distributed along \u223c395 km [245.4 miles] to the south, with about 2 m [6.6 ft] near the capital Nay Pyi Taw.\u201d<\/p>\n A seismic station near Nay Pyi Taw registered ground motion data<\/a> that were \u201cimmediately convincing of supershear rupture given the time between the weak, dilational P wave first arrival and the arrival of large shear offset of the fault\u201d at the station, UC Santa Cruz\u2019s Thorne Lay said in a Seismological Society of America statement<\/a>. An offset<\/a> is the ground displacement that occurs along a fault during an earthquake. \u201cThat was unusually clear and convincing evidence for supershear rupture relative to other long strike-slip events that I have worked on.\u201d<\/p>\n<\/p>\n Lay and his colleagues suggest that the supershear velocity, as well as the rupture\u2019s strong directivity<\/a> (the piling up of S waves in the direction of the fault line as the rupture spreads) toward the south, might have caused the earthquake\u2019s widespread damage.<\/p>\n While the Sagaing Fault frequently causes large earthquakes, the one in March involved a stretch of the fault between the cities of Mandalay and Nay Pyi Taw that has been quiet since 1912. \u201cLonger histories and better understanding of fault segmentation and geometry are needed to have any guidance for future event activity, but I would not expect the central area to fail again before a long period of rebuilding strain energy,\u201d Lay added.<\/p>\n While it is impossible to predict earthquakes with any kind of precision, earthquake early-warning (EEW) systems provide last-minute but still crucial warnings of incoming seismic events by sending out electronic alerts that travel faster than seismic waves. While many seismic regions don\u2019t have the necessary infrastructure for such systems, the smartphone-based Android Earthquake Alerts (AEA) system<\/a> has recently proved to be as efficient as traditional seismic networks.<\/p>\n","protected":false},"excerpt":{"rendered":"On March 28, Myanmar was rocked by a 7.8 magnitude earthquake that claimed over 5,000 lives and caused…\n","protected":false},"author":2,"featured_media":26941,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[14890,23423,79,23424],"class_list":{"0":"post-26940","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-earthquakes","9":"tag-myanmar","10":"tag-science","11":"tag-seismology"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/26940","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=26940"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/26940\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/26941"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=26940"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=26940"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=26940"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}