{"id":41927,"date":"2025-10-27T09:31:26","date_gmt":"2025-10-27T04:01:26","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=41927"},"modified":"2025-10-28T13:36:55","modified_gmt":"2025-10-28T08:06:55","slug":"japan-issues-its-first-ever-megaquake-warning","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/japan-issues-its-first-ever-megaquake-warning\/","title":{"rendered":"Japan Issues its First-Ever &#8216;Megaquake Warning&#8217;"},"content":{"rendered":"<h2><strong>What\u2019s in today\u2019s article?<\/strong><\/h2>\n<ul>\n<li>Why in News?<\/li>\n<li>What Concerns are Japanese Authorities Currently Facing?<\/li>\n<li>Why was Alert Issued if Earthquakes can&#8217;t be Predicted?<\/li>\n<li>What is the Ring of Fire?<\/li>\n<\/ul>\n<h2><strong>Why in News?<\/strong><\/h2>\n<ul>\n<li>A recent earthquake (of magnitude 7.1 on Richter scale) in southern Japan was promptly followed by a major warning from Japan&#8217;s meteorological agency, stating that there was a heightened risk of a first-ever &#8220;mega earthquake&#8221;.<\/li>\n<li>Earthquakes with a <strong>magnitude greater than 8<\/strong> (on Richter scale) are classified as megaquakes.<\/li>\n<\/ul>\n<h2><strong>What Concerns are Japanese Authorities Currently Facing?<\/strong><\/h2>\n<ul>\n<li><strong>Japan is situated on the Ring of Fire:<\/strong>\n<ul>\n<li>Though Japan is <strong>no stranger to seismic activity<\/strong> (experiencing approx. 1,500 earthquakes annually), most of these tremors cause minimal damage.<\/li>\n<li>However, <strong>there have been devastating exceptions<\/strong>, such as the magnitude 9.0 quake that struck in 2011, triggering a tsunami and nuclear disaster that claimed over 18,000 lives along the north-east coast.<\/li>\n<\/ul>\n<\/li>\n<li><strong>The Nankai Trough:<\/strong>\n<ul>\n<li>The Nankai Trough, situated off the southwest Pacific coast of Japan, is a significant geological feature that extends for roughly 900 km (600 miles).<\/li>\n<li>This trough is formed by the subduction of the Philippine Sea Plate beneath the Eurasian Plate.<\/li>\n<li>The convergence of these two tectonic plates along the Nankai Trough results in the <strong>accumulation of immense tectonic strains over time<\/strong>.<\/li>\n<li>These built-up strains have the potential to trigger a devastating megaquake approximately once every 100 to 150 years.<\/li>\n<li><strong>For example,<\/strong> a rupture spanning the entire 600km length of the Nankai Trough triggered Japan&#8217;s 2nd-largest recorded earthquake (followed by the eruption of Mount Fuji) in 1707.<\/li>\n<li>According to experts, there is <strong>a 70% to 80% probability<\/strong> of a magnitude 8 or 9 earthquake occurring somewhere along the trough within the next three decades.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2><strong>Why was Alert Issued if Earthquakes can&#8217;t be Predicted?<\/strong><\/h2>\n<ul>\n<li>According to experts, the issuance of the warning has almost nothing to do with science.<\/li>\n<li>This is because earthquakes are known to be a &#8220;<strong>clustered phenomenon<\/strong>&#8220;, and it is not possible to tell in advance whether a quake is a foreshock or an aftershock.<\/li>\n<li>However, the alert was sent out urging individuals<strong> to be ready for potential evacuation. <\/strong><i>For example,<\/i>in several towns authorities are encouraging elderly residents and others to voluntarily relocate to safer areas.<\/li>\n<\/ul>\n<h2><strong>What is the Ring of Fire?<\/strong><\/h2>\n<ul>\n<li><strong>The <\/strong><a href=\"https:\/\/vajiramandravi.com\/current-affairs\/ring-of-fire\/\" target=\"_blank\">Ring of Fire<\/a><strong> is a tectonic belt of volcanoes and earthquakes<\/strong>, which is about 40,000 km (25,000 mi) long<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ring_of_Fire#cite_note-NOAA_ROF-2\" target=\"_blank\" rel=\"nofollow noopener\">]<\/a> and up to about 500 km (310 mi) wide.<\/li>\n<li>It surrounds most of the <strong>Pacific Ocean, <\/strong>hence it is also called <strong>Circum-Pacific Belt.<\/strong><\/li>\n<li>It contains between 750 and 915 active or dormant volcanoes, which is <strong>around two-thirds <\/strong>of the world total.<\/li>\n<li><strong>About 90% of the world&#8217;s earthquakes<\/strong>, including most of its largest, occur within the belt.<\/li>\n<\/ul>\n<hr \/>\n<h3><strong>Q.1. What is the difference between the mercalli and richter scales of seismic activity?<\/strong><\/h3>\n<p>The Mercalli and Richter scales are both used when measuring the impacts of seismic activity. However, while the Richter scale measures the magnitude\/ force of the earthquake, the Mercalli scale measures the physical impact\/ intensity of the earthquake within a given location.<\/p>\n<h3><strong>Q.2. What is the difference between the epicenter and the focus of an earthquake?<\/strong><\/h3>\n<p>The focus is the place inside Earth&#8217;s crust where an earthquake originates. The point on the Earth&#8217;s surface directly above the focus is the epicenter.<\/p>\n<p><strong>Source: <\/strong><a href=\"https:\/\/www.thehindu.com\/sci-tech\/science\/japan-megaquake-warning-explained\/article68505573.ece\" target=\"_blank\" rel=\"nofollow noopener\">Japan\u2019s \u2018megaquake\u2018 warning | Explained<\/a> | <a href=\"https:\/\/timesofindia.indiatimes.com\/world\/rest-of-world\/japan-issues-its-first-ever-megaquake-warning-know-all-about-big-one\/articleshow\/112448503.cms\" target=\"_blank\" rel=\"nofollow noopener\">ToI<\/a> | <a href=\"https:\/\/indianexpress.com\/article\/explained\/explained-sci-tech\/japan-megaquake-advisory-9506703\/\" target=\"_blank\" rel=\"nofollow noopener\">IE<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A recent earthquake in southern Japan was promptly followed by a first-ever &#8220;mega earthquake&#8221; warning from Japan&#8217;s meteorological agency<\/p>\n","protected":false},"author":5,"featured_media":41928,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[],"class_list":{"0":"post-41927","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-mains-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/41927","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=41927"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/41927\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/41928"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=41927"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=41927"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=41927"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}