{"id":62,"date":"2020-12-15T11:54:20","date_gmt":"2020-12-15T16:54:20","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/?post_type=chapter&#038;p=62"},"modified":"2020-12-21T16:58:49","modified_gmt":"2020-12-21T21:58:49","slug":"earthquakes","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/chapter\/earthquakes\/","title":{"raw":"Earthquakes &amp; Seismic Waves","rendered":"Earthquakes &amp; Seismic Waves"},"content":{"raw":"<h5>Learn about what earthquakes are, how we measure them, and how we use seismic waves to investigate Earth's interior.<\/h5>\r\n&nbsp;\r\n\r\n<em>If you're interested in how seismic waves are used to study Earth's insides, you might also like this video:<\/em>\r\n<table class=\"lines landscape\" border=\"0\">\r\n<tbody>\r\n<tr>\r\n<td><img class=\"wp-image-69 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain-217x300.jpg\" alt=\"\" width=\"74\" height=\"102\" \/><\/td>\r\n<td><strong>How Do We Know About Earth's Core?<\/strong> Learn about how P-wave and S-wave shadow zones reveal the nature of Earth's inner and outer core. <a href=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/chapter\/chapter-2-plate-tectonics\/#Khan-core\" target=\"_blank\" rel=\"noopener noreferrer\">Go!<\/a><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n&nbsp;\r\n\r\n<img class=\"wp-image-201 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png\" alt=\"\" width=\"195\" height=\"217\" \/>\r\n<h1><span style=\"color: #000000\"><a id=\"SciShow_Earthquake\" style=\"color: #000000\"><\/a>Earthquake Science, and the Disaster That Created It<\/span><\/h1>\r\nA video by <a href=\"https:\/\/www.youtube.com\/channel\/UCZYTClx2T1of7BRZ86-8fow\" target=\"_blank\" rel=\"noopener noreferrer\">SciShow<\/a>. The resources accompanying this video were created by <strong>Sabrina Warwick<\/strong> and are shared with a CC BY-SA license.\r\n\r\n&nbsp;\r\n\r\nhttps:\/\/youtu.be\/XOCxNVDiOnE\r\n<h2>Summary<\/h2>\r\nThe content explored is designed to help the viewer understand the ways in which the 1964 Alaskan Earthquake disaster (and earthquakes alike) help scientists to understand the reasons for why and how tectonic plates can cause catastrophic damage. This video entails an informative description of how an earthquake with a magnitude over 9.0 is possible. It explores the ways in which tectonic plate boundaries can interact, and the implications of these interactions.\r\n<h2>Why Watch This Video?<\/h2>\r\n<ul>\r\n \t<li>Have you ever wondered what type of tectonic plate interaction warrants a 9.0 earthquake?<\/li>\r\n \t<li>Would you like to know why some earthquakes can be felt when not close to a boundary line (a place where tectonic plates interact)?<\/li>\r\n \t<li>Have you ever been confused by the mechanics of what is actually happening between tectonic plates when an earthquake occurs?<\/li>\r\n<\/ul>\r\n<h2>Key Terms<\/h2>\r\n<strong>Plate boundaries<\/strong> are faults within the lithosphere. The way the tectonic plates interact with each other is what determines the type of plate boundary. There are three different ways a plate can interact with another: divergent boundary (moving apart), convergent boundary (colliding together), and transformation boundary (sliding beside each other).\r\n\r\n<strong>Faults<\/strong> are breaks within the lithosphere. These faults can be plate boundaries or breaks within the crust that are in the middle of tectonic plates. Different types of faults are the result of different types of stress being put on the rock. The types of faults that can occur are normal, reverse, and strike-slip faults.\r\n\r\nA <strong>megathrust<\/strong> is another way to explain the process of subduction on a large scale. One tectonic plate moves beneath another. Energy builds up between the plates and one of them rebounds back to its original shape. This type of rebound is called elastic rebound and is when a rock snaps back into shape and the vibrations are interpreted as an earthquake. A megathrust is an earthquake that occurs along continent-continent convergence boundaries.\r\n<h2>Loose Ends<\/h2>\r\n<h3>How many plates actually exist?<\/h3>\r\nThe video states that there are seven tectonic plates. This is true in the sense that there are seven major plates, but there are many smaller plates that make up the lithosphere. There are actually 15 in total, although even more if the tiniest plate fragments are counted.\r\n<h3>Why do tectonic plates move?<\/h3>\r\nThe video doesn\u2019t exactly state why tectonic plates are able to move. The lithosphere makes up the Earth\u2019s crust and it is the layer that sits on the asthenosphere. The lithospheric plates are able to move as the asthenosphere is not as rigid as the lithosphere; it is weak and has melted areas. These characteristics of the asthenosphere are what makes it possible for the lithosphere to move easily atop the asthenosphere.\r\n\r\n&nbsp;\r\n<div class=\"textbox shaded\">\r\n<h3><img class=\"wp-image-53 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-300x300.png\" alt=\"\" width=\"67\" height=\"67\" \/>Caution: the term \"recycling\" of tectonic plates isn't entirely correct.<\/h3>\r\nThe concept of subduction in this video isn\u2019t fully explained. There are two theories: whole mantle convection and double layered convection. The whole mantle theory states that magma gets pushed up towards the crust due to its low density, cools near the top and then sinks back to the very bottom of the mantle. The double layered mantle theory states that the upper and lower mantle are actually too different to convect as one; some lithospheric slabs do not sink all the way through to the bottom. The mantle has specific areas in which melting happens; it\u2019s not entirely molten nor solid. These melting areas are due to chemical, temperature or pressure changes.\r\n\r\n<\/div>\r\n&nbsp;\r\n<h2>Self-Test<\/h2>\r\nTry these questions to test your understanding.\r\n\r\n&nbsp;\r\n\r\n[h5p id=\"104\"]\r\n<h2>References<\/h2>\r\nSciShow. \u201cEarthquake Science, and the Disaster That Created It.\u201d <em>YouTube<\/em>, YouTube, 13 June 2014.\r\n\r\nPanchuk, K. M. (2019).\u00a0<em>Chapter 4. Plate Tectonics<\/em>. <a href=\"https:\/\/openpress.usask.ca\/physicalgeology\/\" target=\"_blank\" rel=\"noopener noreferrer\">Physical Geology, 1st USask Edition<\/a>.\r\n\r\n&nbsp;\r\n\r\n<img class=\"wp-image-201 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png\" alt=\"\" width=\"172\" height=\"191\" \/>","rendered":"<h5>Learn about what earthquakes are, how we measure them, and how we use seismic waves to investigate Earth&#8217;s interior.<\/h5>\n<p>&nbsp;<\/p>\n<p><em>If you&#8217;re interested in how seismic waves are used to study Earth&#8217;s insides, you might also like this video:<\/em><\/p>\n<table class=\"lines landscape\">\n<tbody>\n<tr>\n<td><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-69 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain-217x300.jpg\" alt=\"\" width=\"74\" height=\"102\" srcset=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain-217x300.jpg 217w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain-65x90.jpg 65w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain-225x311.jpg 225w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/core-of-the-Earth-publicdomain.jpg 311w\" sizes=\"auto, (max-width: 74px) 100vw, 74px\" \/><\/td>\n<td><strong>How Do We Know About Earth&#8217;s Core?<\/strong> Learn about how P-wave and S-wave shadow zones reveal the nature of Earth&#8217;s inner and outer core. <a href=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/chapter\/chapter-2-plate-tectonics\/#Khan-core\" target=\"_blank\" rel=\"noopener noreferrer\">Go!<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-201 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png\" alt=\"\" width=\"195\" height=\"217\" srcset=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png 270w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-922x1024.png 922w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-768x853.png 768w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-1382x1536.png 1382w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-1843x2048.png 1843w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-65x72.png 65w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-225x250.png 225w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-350x389.png 350w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings.png 1873w\" sizes=\"auto, (max-width: 195px) 100vw, 195px\" \/><\/p>\n<h1><span style=\"color: #000000\"><a id=\"SciShow_Earthquake\" style=\"color: #000000\"><\/a>Earthquake Science, and the Disaster That Created It<\/span><\/h1>\n<p>A video by <a href=\"https:\/\/www.youtube.com\/channel\/UCZYTClx2T1of7BRZ86-8fow\" target=\"_blank\" rel=\"noopener noreferrer\">SciShow<\/a>. The resources accompanying this video were created by <strong>Sabrina Warwick<\/strong> and are shared with a CC BY-SA license.<\/p>\n<p>&nbsp;<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Earthquake Science, and the Disaster That Created It\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/XOCxNVDiOnE?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<h2>Summary<\/h2>\n<p>The content explored is designed to help the viewer understand the ways in which the 1964 Alaskan Earthquake disaster (and earthquakes alike) help scientists to understand the reasons for why and how tectonic plates can cause catastrophic damage. This video entails an informative description of how an earthquake with a magnitude over 9.0 is possible. It explores the ways in which tectonic plate boundaries can interact, and the implications of these interactions.<\/p>\n<h2>Why Watch This Video?<\/h2>\n<ul>\n<li>Have you ever wondered what type of tectonic plate interaction warrants a 9.0 earthquake?<\/li>\n<li>Would you like to know why some earthquakes can be felt when not close to a boundary line (a place where tectonic plates interact)?<\/li>\n<li>Have you ever been confused by the mechanics of what is actually happening between tectonic plates when an earthquake occurs?<\/li>\n<\/ul>\n<h2>Key Terms<\/h2>\n<p><strong>Plate boundaries<\/strong> are faults within the lithosphere. The way the tectonic plates interact with each other is what determines the type of plate boundary. There are three different ways a plate can interact with another: divergent boundary (moving apart), convergent boundary (colliding together), and transformation boundary (sliding beside each other).<\/p>\n<p><strong>Faults<\/strong> are breaks within the lithosphere. These faults can be plate boundaries or breaks within the crust that are in the middle of tectonic plates. Different types of faults are the result of different types of stress being put on the rock. The types of faults that can occur are normal, reverse, and strike-slip faults.<\/p>\n<p>A <strong>megathrust<\/strong> is another way to explain the process of subduction on a large scale. One tectonic plate moves beneath another. Energy builds up between the plates and one of them rebounds back to its original shape. This type of rebound is called elastic rebound and is when a rock snaps back into shape and the vibrations are interpreted as an earthquake. A megathrust is an earthquake that occurs along continent-continent convergence boundaries.<\/p>\n<h2>Loose Ends<\/h2>\n<h3>How many plates actually exist?<\/h3>\n<p>The video states that there are seven tectonic plates. This is true in the sense that there are seven major plates, but there are many smaller plates that make up the lithosphere. There are actually 15 in total, although even more if the tiniest plate fragments are counted.<\/p>\n<h3>Why do tectonic plates move?<\/h3>\n<p>The video doesn\u2019t exactly state why tectonic plates are able to move. The lithosphere makes up the Earth\u2019s crust and it is the layer that sits on the asthenosphere. The lithospheric plates are able to move as the asthenosphere is not as rigid as the lithosphere; it is weak and has melted areas. These characteristics of the asthenosphere are what makes it possible for the lithosphere to move easily atop the asthenosphere.<\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">\n<h3><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-53 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-300x300.png\" alt=\"\" width=\"67\" height=\"67\" srcset=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-300x300.png 300w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-1024x1024.png 1024w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-150x150.png 150w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-768x768.png 768w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-1536x1536.png 1536w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-2048x2048.png 2048w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-65x65.png 65w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-225x225.png 225w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/08\/5a81af7d9123fa7bcc9b0793-350x350.png 350w\" sizes=\"auto, (max-width: 67px) 100vw, 67px\" \/>Caution: the term &#8220;recycling&#8221; of tectonic plates isn&#8217;t entirely correct.<\/h3>\n<p>The concept of subduction in this video isn\u2019t fully explained. There are two theories: whole mantle convection and double layered convection. The whole mantle theory states that magma gets pushed up towards the crust due to its low density, cools near the top and then sinks back to the very bottom of the mantle. The double layered mantle theory states that the upper and lower mantle are actually too different to convect as one; some lithospheric slabs do not sink all the way through to the bottom. The mantle has specific areas in which melting happens; it\u2019s not entirely molten nor solid. These melting areas are due to chemical, temperature or pressure changes.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<h2>Self-Test<\/h2>\n<p>Try these questions to test your understanding.<\/p>\n<p>&nbsp;<\/p>\n<div id=\"h5p-104\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-104\" class=\"h5p-iframe\" data-content-id=\"104\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2020T1-Warwick\"><\/iframe><\/div>\n<\/div>\n<h2>References<\/h2>\n<p>SciShow. \u201cEarthquake Science, and the Disaster That Created It.\u201d <em>YouTube<\/em>, YouTube, 13 June 2014.<\/p>\n<p>Panchuk, K. M. (2019).\u00a0<em>Chapter 4. Plate Tectonics<\/em>. <a href=\"https:\/\/openpress.usask.ca\/physicalgeology\/\" target=\"_blank\" rel=\"noopener noreferrer\">Physical Geology, 1st USask Edition<\/a>.<\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-201 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png\" alt=\"\" width=\"172\" height=\"191\" srcset=\"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-270x300.png 270w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-922x1024.png 922w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-768x853.png 768w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-1382x1536.png 1382w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-1843x2048.png 1843w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-65x72.png 65w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-225x250.png 225w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings-350x389.png 350w, https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-content\/uploads\/sites\/1111\/2020\/12\/buildings.png 1873w\" sizes=\"auto, (max-width: 172px) 100vw, 172px\" \/><\/p>\n","protected":false},"author":1019,"menu_order":6,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-62","chapter","type-chapter","status-web-only","hentry"],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapters\/62","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/wp\/v2\/users\/1019"}],"version-history":[{"count":24,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapters\/62\/revisions"}],"predecessor-version":[{"id":204,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapters\/62\/revisions\/204"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapters\/62\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/wp\/v2\/media?parent=62"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/pressbooks\/v2\/chapter-type?post=62"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/wp\/v2\/contributor?post=62"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/showmeearthscience\/wp-json\/wp\/v2\/license?post=62"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}