{"id":1395,"date":"2020-03-30T14:58:02","date_gmt":"2020-03-30T09:28:02","guid":{"rendered":"https:\/\/knowledgekart.in\/blog\/?p=1395"},"modified":"2020-03-30T15:06:02","modified_gmt":"2020-03-30T09:36:02","slug":"ncert-notes-earthquake-body-waves-causes-types","status":"publish","type":"post","link":"https:\/\/knowledgekart.in\/blog\/ncert-notes-earthquake-body-waves-causes-types\/","title":{"rendered":"NCERT Notes Earthquake Body Waves, Causes &#038; Types [Geography Notes For UPSC]"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"> NCERT notes on important topics for the UPSC Civil Services Exam.  These notes will also be useful for other competitive exams like  banking PO, SSC, and so on. This article talks about Earthquakes, its  magnitude scale, causes, types, etc. NCERT Notes Earthquake<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Earthquake \u2013 Body Waves, Causes &amp; Types<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"> <strong>Earthquake <\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>All natural earthquakes occur in the lithosphere.<\/li><li>Seismic waves studies offer a full picture of the layered interior.<\/li><li>An earthquake is, simply put, shaking of the earth\u2019s crust.<\/li><li>It is caused due to the energy release, which triggers waves that travel in all directions.<\/li><li>The emanation of energy occurs along a fault.<\/li><li>A fault is a sharp break in the crustal rocks.<\/li><li>Rocks along a fault generally move in opposing directions.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"> <strong>Types of Earthquakes <\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Tectonic <\/strong><strong>earthquakes:<\/strong>&nbsp;The most \ncommon form of earthquakes, it is caused by the movement of loose \nfragmented pieces of land on earth\u2019s crust knowns as tectonic plates.<\/li><li><strong>Volcanic <\/strong><strong>earthquake:<\/strong>&nbsp;The less prevalent compared to the tectonic variety, these earthquakes happen before or after the eruption of a <a href=\"https:\/\/byjus.com\/free-ias-prep\/ncert-notes-geography-volcanoes\/\" target=\"_blank\" rel=\"noopener\">volcano<\/a>. It is caused when magma leaving the volcano are filled by rocks being pushed to the surface.<\/li><li><strong>Collapse <\/strong><strong>earthquake:<\/strong>&nbsp;This earthquake occurs in underground mines. The main cause is due to pressure generated within the rocks.<\/li><li><strong>Explosion <\/strong><strong>earthquakes:<\/strong> The \noccurrence of this type of earthquake is artificial in nature. \nHigh-density explosion such as nuclear explosions is the primary cause.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong> Causes of Earthquakes <\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>It is caused due to the tectonic movements of the earth.<\/li><li>The energy release produces waves which travel in all directions.<\/li><li>The point where energy is released is called the&nbsp;focus or hypocentre<strong>.<\/strong>&nbsp;It is generally located at a depth of 60 km.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>This causes a release of energy, and the energy waves travel in all directions.<\/li><li>The point where the energy is released is called the focus of an earthquake or hypocentre.<\/li><li>The point on the surface of the earth which is vertically above the \nfocus is called the epicentre. It is the first place to experience the \nwaves.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"> <strong>Body Waves <\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Earthquake waves are of two types \u2014 body waves and surface waves.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>P- Waves<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>P-waves are also known as the Primary waves. They are the first waves to arrive at the surface.<\/li><li>The characteristics of P-waves are like sound waves. They travel through all three mediums- solid, liquid and gas.<\/li><li>These waves have a tendency to vibrate parallel to the direction of \nwave propagation. This causes density differences in the material \nthrough which they travel.<\/li><li>These waves are responsible for elongating and squeezing of material.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>S- Waves<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>S- Waves arrive after some time after the happening of Earthquake and they are called secondary waves.<\/li><li>A significant characteristic of these S-waves is that they travel only through a solid medium.<\/li><li>The direction of vibration of this S-wave is perpendicular to the \ndirection of wave propagation, thereby creating crests and troughs in \nthe material of their transmission.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong> Shadow Zone <\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" width=\"399\" height=\"804\" src=\"https:\/\/knowledgekart.in\/blog\/wp-content\/uploads\/NCET-earthquake.jpg\" alt=\"NCERT Notes Earthquake - Body Waves, Causes &amp; Types [Geography Notes For UPSC]\" class=\"wp-image-1396\" title=\"\" srcset=\"https:\/\/knowledgekart.in\/blog\/wp-content\/uploads\/\/NCET-earthquake.jpg 399w, https:\/\/knowledgekart.in\/blog\/wp-content\/uploads\/\/NCET-earthquake-149x300.jpg 149w\" sizes=\"(max-width: 399px) 100vw, 399px\" \/><\/figure><\/div>\n\n\n\n<ul class=\"wp-block-list\"><li>The shadow zone is the zone of the earth from angular distances of \n104 to 140 degrees from a given earthquake that does not receive any \ndirect P waves.<\/li><li>The shadow zone results from P waves being refracted by the liquid core and S waves being stopped completely by the liquid core.<\/li><li>A zone between 105\u00b0 and 145\u00b0 from the&nbsp;epicentre was recognised as the shadow zone for both the waves types.<\/li><li>The entire zone beyond 105\u00b0 does not receive S-waves.<\/li><li>The shadow zone of S-wave is larger than that of the P-waves.<\/li><li>The shadow zone of P-waves appears as a band around the earth between 105\u00b0 and 145\u00b0 away from the epicentre.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong> Effects of earthquake <\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The following are the immediate hazardous effects of Earthquake:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Shaking of ground<\/li><li>The disparity in ground settlement<\/li><li>Natural disasters like <a href=\"https:\/\/byjus.com\/free-ias-prep\/tsumani\/\" target=\"_blank\" rel=\"noopener\">Tsunami<\/a>, landslide, mudslides and avalanches<\/li><li>Soil liquefaction<\/li><li>Ground lurching and displacement<\/li><li><a href=\"https:\/\/byjus.com\/free-ias-prep\/floods\/\" target=\"_blank\" rel=\"noopener\">Floods<\/a> and fires<\/li><li>Infrastructure collapse.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">NCERT Notes Earthquake<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"> <strong>Measurement <\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">All earthquakes are different in their \nintensity and magnitude. The instrument for the measurement of the \nvibrations is known as Seismograph.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Magnitude scale<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/byjus.com\/free-ias-prep\/richter-scale\/\" target=\"_blank\" rel=\"noopener\">Richter scale<\/a> is used to measure the magnitude of the earthquake<\/li><li>The energy released during a quake is expressed in absolute numbers of 0-10.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Intensity scale<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>The Mercalli scale is used to measure the intensity of an earthquake<\/li><li>It measures the visible damage caused due to the quake.<\/li><li>It is expressed in the range of 1-12.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">NCERT Notes Earthquake<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"http:\/\/upsc.gov.in\" target=\"_blank\" rel=\"noopener\">UPSC<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"http:\/\/knowledgekart.in\">Click Here to read more<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>NCERT notes on important topics for the UPSC Civil Services Exam. These notes will also be useful for other competitive exams like banking PO, SSC, and so on. This article&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[114],"tags":[],"class_list":["post-1395","post","type-post","status-publish","format-standard","hentry","category-geography"],"_links":{"self":[{"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/posts\/1395","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/comments?post=1395"}],"version-history":[{"count":0,"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/posts\/1395\/revisions"}],"wp:attachment":[{"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/media?parent=1395"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/categories?post=1395"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/knowledgekart.in\/blog\/wp-json\/wp\/v2\/tags?post=1395"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}