{"id":26451,"date":"2020-04-14T08:06:37","date_gmt":"2020-04-14T08:06:37","guid":{"rendered":"https:\/\/www.bgs.ac.uk\/discover-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/"},"modified":"2021-06-10T11:51:18","modified_gmt":"2021-06-10T11:51:18","slug":"what-causes-earthquakes","status":"publish","type":"page","link":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/","title":{"rendered":"What causes earthquakes?"},"content":{"rendered":"\t\t\t<section class=\"hero-section hero-section-with-social\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info-wrap\">\n\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info\">\n\t\t\t\t\t\t\t\t\t<h1>What causes earthquakes?<\/h1>\n\t\t\t\t\t\t\t\t\t<p>Discovering Geology &mdash; Earthquakes<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n\t\t\t<div class=\"social-wrap social-wrap-inline-them\">\n\t\t\t\t<div class=\"sea-background-f\">\n\t\t\t\t\t<span>Share this article<\/span><a target=\"_blank\"  href=\"https:\/\/www.facebook.com\/sharer\/sharer.php?u=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\"><span class=\"icon-facebook\"><span class=\"hidden\">Facebook<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/twitter.com\/intent\/tweet?text=What%20causes%20earthquakes?&#038;url=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\"><span class=\"icon-twitter\"><span class=\"hidden\">Twitter<\/span><\/span><\/a><a   onclick=\"javascript:void( (function() {var e=document.createElement('script' );e.setAttribute('type','text\/javascript' );e.setAttribute('charset','UTF-8' );e.setAttribute('src','\/\/assets.pinterest.com\/js\/pinmarklet.js?r='+Math.random()*99999999);document.body.appendChild(e)})());\"  href=\"javascript:void(0);\"><span class=\"icon-pinterest\"><span class=\"hidden\">Pinterest<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/wa.me?text=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\"><span class=\"icon-whatsapp\"><span class=\"hidden\">WhatsApp<\/span><\/span><\/a><a   href=\"mailto:?subject=What%20causes%20earthquakes?&#038;body=The%20causes%20of%20earthquakes%20and%20the%20different%20types%20of%20tectonic%20boundaries%20and%20faults%20on%20which%20they%20usually%20occur.%20(https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/)\"><span class=\"icon-mail\"><span class=\"hidden\">Email<\/span><\/span><\/a><a href=\"#\" data-copy=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\" class=\"copy-url-on-click\"><span class=\"icon-link\"><span class=\"hidden\">Copy Link<\/span><\/span><\/a><\/div><\/div>\t\t\t\t\t\t\t<\/section>\n\t\t\t\n\n\n<section class=\"wp-block-bgs-blocks-content-container content-section\"><div class=\"container\"><div class=\"row\"><div class=\"col-12\">\n<p>Earthquakes are the result of sudden movement along faults within the Earth. The movement releases stored-up &#8216;elastic strain&#8217; energy in the form of seismic waves, which propagate through the Earth and cause the ground surface to shake. Such movement on the faults is generally a response to long-term deformation and the buildup of stress.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The structure of the Earth<\/h2>\n\n\n\n<p>Seismic waves from large earthquakes pass throughout the Earth. These waves contain vital information about the internal structure of the Earth. As seismic waves pass through the Earth, they are refracted, or bent, like rays of light bend when they pass through a glass prism. Because the speed of the seismic waves depends on density, we can use the travel-time of seismic waves to map change in density with depth and show that the Earth is composed of several layers. <\/p>\n\n\n\t\t\t\t<div  class=\"owl-carousel carousel-primary-color carousel owl-theme thumbs-carousel-js\">\n\t\t\t\t\t<div class=\"item\"><figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/earthStructureDimensions.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Inner structure of the Earth. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_81245\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/earthStructureDimensions.jpg\" class=\"attachment-medium size-medium\" alt=\"Inner structure of the Earth\" \/><\/a><figcaption class=\"caption sm-line\">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Inner structure of the Earth. BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/earthStructureDimensions.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Inner structure of the Earth. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_81245\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure><\/div><div class=\"item\"><figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Hypothetical_PWaves_BGS.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;P-waves of a hypothetical earthquake at the North Pole are refracted at the core\u2013mantle boundary and shadow zones are created. Although P-waves reappear, S-waves do not. BGS \u00a9UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_81245\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Hypothetical_PWaves_BGS.jpg\" class=\"attachment-medium size-medium\" alt=\"Hypothetical P-waves\" \/><\/a><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>P-waves of a hypothetical earthquake at the North Pole are refracted at the core\u2013mantle boundary and shadow zones are created. Although P-waves reappear, S-waves do not. BGS \u00a9UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Hypothetical_PWaves_BGS.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;P-waves of a hypothetical earthquake at the North Pole are refracted at the core\u2013mantle boundary and shadow zones are created. Although P-waves reappear, S-waves do not. BGS \u00a9UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_81245\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure><\/div>\t\t\t\t<\/div>\n\t\t\t\t\n\n<div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">The crust<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>This brittle, outermost layer varies in thickness from about 25 to 70 km under continents and from about 5 to 10\u00a0km under the oceans. Continental crust is quite complex in structure and is made from many different kinds of rocks.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">The mantle<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>Below the crust lies the dense mantle, extending to a depth of 2890\u00a0km. It consists of dense silicate rocks. Both P- and S-waves from earthquakes travel through the mantle, demonstrating that it is solid.<\/p>\n<p>However, there is separate evidence that parts of\u00a0 the mantle behaves as a fluid over very long geological times scales, with rocks flowing slowly in giant convection cells.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">The core<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>At a depth of about 2900 km is the boundary between the mantle and the Earth&#8217;s core. The core is composed of iron and we know that it exists because it refracts seismic waves creating a &#8216;shadow zone&#8217; at distances between 103\u00ba and 143\u00ba. We also know that the outer part of the core is liquid, because S-waves do not pass through it.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div>\n\n\n<h2 class=\"wp-block-heading\" id=\"tectonics\">Plate tectonics<\/h2>\n\n\n\n<p>The Earth\u2019s outermost layer is fragmented into about 15 major slabs called tectonic plates. These slabs form the lithosphere, which is comprised of&nbsp;the crust (continental and oceanic) and the upper part of the mantle. Tectonic plates move very slowly relative to each other, typically a few centimetres per year, but this still causes a huge amount of deformation at the plate boundaries, which in turn results in earthquakes.<\/p>\n\n\n\n<p>Observations show that most earthquakes are associated with tectonic plate boundaries and the theory of plate tectonics can be used to provide a simplified explanation of the global distribution of earthquakes, while some of the characteristics of earthquakes can be explained by using a simple elastic rebound theory.<\/p>\n\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/08\/tectonic-plates-movement-1400x730.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Plate tectonic map of the world showing direction of movement. BGS \u00a9UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_64371\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/08\/tectonic-plates-movement-150x150.jpg\" class=\"lazy-blur\" alt=\"Plate tectonic map of the world showing direction of movement\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/08\/tectonic-plates-movement-960x501.jpg\" \/><\/a><figcaption class=\"caption sm-line\">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Plate tectonic map of the world showing direction of movement. BGS \u00a9UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/08\/tectonic-plates-movement-1400x730.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Plate tectonic map of the world showing direction of movement. BGS \u00a9UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_64371\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure>\n\n\n<h2 class=\"wp-block-heading\" id=\"drivers\">What drives the movement of tectonic plates?<\/h2>\n\n\n\n<p>Below the tectonic plates lies the Earth\u2019s asthenosphere. The asthenosphere behaves like a fluid over very long time scales. There are a number of competing theories that attempt to explain what drives the movement of tectonic plates. Three of the forces that have been proposed as the main drivers of tectonic plate movement are:<\/p>\n\n\n\n<ul><li>mantle convection currents: warm mantle currents drive and carry plates of lithosphere along a like a conveyor belt<\/li><li>ridge push (buoyant upwelling mantle at mid-ocean ridges): newly formed plates at oceanic ridges are warm, so they have a higher elevation at the oceanic ridge than the colder, more dense plate material further away; gravity causes the higher plate at the ridge to push away the lithosphere that lies further from the ridge<\/li><li>slab pull: older, colder plates sink at subduction zones because, as they cool, they become more dense than the underlying mantle and the cooler, sinking plate pulls the rest of the warmer plate along behind it<\/li><\/ul>\n\n\n\n<p><a href=\"http:\/\/www.nature.com\/ngeo\/journal\/v8\/n6\/full\/ngeo2431.html?WT.ec_id=NGEO-201506\" target=\"_blank\" rel=\"noreferrer noopener\">Research<\/a> has shown that the&nbsp;major&nbsp;driving force for most plate movement is slab pull, because the plates with more of their edges being subducted are the faster-moving ones. However, ridge push is also presented in recent research to be a force that drives the movement of plates.<\/p>\n\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/Convection_currents_BGS.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Mantle convection currents, ridge push and slab pull are three of the forces that have been proposed as the main drivers of plate movement (based on &lt;a href=&quot;https:\/\/www.earthlearningidea.com\/PDF\/217_Slab_pull.pdf&quot; target=&quot;_blank&quot; rel=&quot;noopener&quot;&gt;What drives the plates?&lt;\/a&gt;). BGS \u00a9 UKRI. All rights reserved.&lt;\/p&gt;\n\" data-gallery=\"gallery_40533\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/Convection_currents_BGS-150x150.jpg\" class=\"lazy-blur\" alt=\"What drives plate tectonics\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/Convection_currents_BGS.jpg\" \/><\/a><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Mantle convection currents, ridge push and slab pull are three of the forces that have been proposed as the main drivers of plate movement (based on <a href=\"https:\/\/www.earthlearningidea.com\/PDF\/217_Slab_pull.pdf\" target=\"_blank\" rel=\"noopener\">What drives the plates?<\/a>). BGS \u00a9 UKRI. All rights reserved.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/Convection_currents_BGS.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Mantle convection currents, ridge push and slab pull are three of the forces that have been proposed as the main drivers of plate movement (based on &lt;a href=&quot;https:\/\/www.earthlearningidea.com\/PDF\/217_Slab_pull.pdf&quot; target=&quot;_blank&quot; rel=&quot;noopener&quot;&gt;What drives the plates?&lt;\/a&gt;). BGS \u00a9 UKRI. All rights reserved.&lt;\/p&gt;\n\" data-gallery=\"gallery_40533\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure>\n\n\n<h2 class=\"wp-block-heading\" id=\"boundary\">Types of plate boundary<\/h2>\n\n\n\n<p>There are three types of plated boundary:<\/p>\n\n\n\n<ul><li>divergent: plates moving apart<\/li><li>convergent: plates coming together<\/li><li>transform: plates moving past each other<\/li><\/ul>\n\n\n\n<p>Boundaries between tectonic plates are made up of a system of&nbsp;faults. Each type of boundary is associated with one of three basic&nbsp;types of fault, called normal, reverse and strike-slip faults.<\/p>\n\n\n<div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Divergent boundary<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>Plates can move apart at a boundary. This type of boundary is called a\u00a0divergent boundary. It is also referred to as a constructive plate boundary, as new material is being produced at the boundary surface. This type of boundary is dominated by normal faulting, although other types of faulting may be observed.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_27619\" aria-describedby=\"caption-attachment-27619\" style=\"width: 666px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-27619 size-full\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Divergent_constructive_BGS.jpg\" alt=\"A divergent, or constructive plate boundary\" width=\"666\" height=\"345\" \/><figcaption id=\"caption-attachment-27619\" class=\"wp-caption-text\">A divergent, or constructive, plate boundary, where new material is produced at the surface. The Mid-Atlantic Ridge is a good example of a constructive plate boundary. You can see normal faulting at the surface where the Mid-Atlantic Ridge crosses Iceland. BGS \u00a9UKRI. All rights reserved.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Hot magma rises from the mantle at mid-ocean ridges, pushing the plates apart. Earthquakes occur along the fractures that appear as the plates move apart. Examples include the East African rift and mid-ocean ridges where two ocean plates are moving apart, such as the regions near the Azores and Iceland. Divergent boundaries are associated with volcanic activity and the earthquakes in these zones tend to be frequent and small.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Convergent boundary<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>Continental collisions result in the creation of mountains and fold belts as the rocks are forced upwards. Plates can move towards each other at a boundary. This type of boundary is called a convergent boundary and is dominated by reverse faulting, although other types of faulting may be observed.<\/p>\n<figure id=\"attachment_27617\" aria-describedby=\"caption-attachment-27617\" style=\"width: 666px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-27617 size-full\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_BGS.jpg\" alt=\"A convergent plate boundary showing the subduction of an oceanic plate\" width=\"666\" height=\"345\" \/><figcaption id=\"caption-attachment-27617\" class=\"wp-caption-text\">A convergent, or destructive, boundary showing subduction of an oceanic plate under a continental plate. BGS \u00a9UKRI. All rights reserved.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>When the boundary is between an oceanic plate and a continental plate, it is also referred to as a\u00a0destructive plate boundary. At subduction zones, the oceanic plate is pushed down, or subducted, below the continental lithosphere. As the oceanic slab descends, earthquakes are generated within the slab and at the interface between the plates.<\/p>\n<p>Destructive plate boundaries include deep ocean trenches like the Peru\u2013Chile trench, where the Nazca plate (an oceanic plate) is being\u00a0subducted under the South American (continental) plate, i.e. the oceanic plate is forced underneath the continental plate. These boundaries tend to produce most of the earthquakes that have magnitudes greater than 6.0. Subduction zones also produce the deepest earthquakes.<\/p>\n<p>Where the boundary is between two continental plates, one plate crumples upwards over the other instead of one plate being subducted. Examples include the boundary between the Eurasian plate and the African plate, forming the Alps, and the boundary between the Indian plate and the Eurasian plate, where the Himalayas are formed where the Eurasian plate is forced up and over the Indian plate.<\/p>\n<p>This type of boundary tends to produce a\u00a0diffuse\u00a0zone of activity. Continental collisions result in the creation of mountains and fold belts as the rocks are forced upwards.<\/p>\n<figure id=\"attachment_27618\" aria-describedby=\"caption-attachment-27618\" style=\"width: 666px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-27618 size-full\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_Mountains_BGS.jpg\" alt=\"A convergent plate boundary showing mountain formation\" width=\"666\" height=\"345\" \/><figcaption id=\"caption-attachment-27618\" class=\"wp-caption-text\">A convergent boundary showing mountain formation where one continental plate crumples up and over another continental plate. Reverse faults (or &#8216;thrust&#8217; faults) are found at convergent boundaries. They are associated with mountain ranges, such as the Himalayas or the Alps. BGS \u00a9UKRI.\u00a0<\/figcaption><\/figure>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Transform boundary<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>Plates can move past each other in the same plane at a boundary. This type of boundary is called a\u00a0transform boundary. This type of boundary is dominated by strike-slip faulting, although other types of faulting may be observed.<\/p>\n<p>Where two plates slide past each other, earthquakes originate at shallow depths. This type of plate boundary is also referred to as a conservative plate boundary, as it involves movement but no loss or creation of material at the surface. Examples include the San Andreas fault in the USA and the Anatolian fault in Asia Minor.<\/p>\n<figure id=\"attachment_27616\" aria-describedby=\"caption-attachment-27616\" style=\"width: 666px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-27616 size-full\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Transform_BGS.jpg\" alt=\"A transform boundary\" width=\"666\" height=\"345\" \/><figcaption id=\"caption-attachment-27616\" class=\"wp-caption-text\">A transform boundary, where two plates slide past each other in the same plane. Strike-slip faults occur at transform boundaries: for example, a system of strike-slip faults makes up the transform boundary of the San Andreas fault. BGS \u00a9UKRI.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Transform boundaries typically produce large, shallow-focus earthquakes. Although earthquakes do occur in the central regions of plates, these regions do not usually have large earthquakes.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div>\n\n\n<h2 class=\"wp-block-heading\" id=\"rebound\">Elastic rebound theory<\/h2>\n\n\n\n<p>Elastic rebound theory was originally proposed after the great San Francisco earthquake in 1906 by the geologist Henry Fielding Reid, to explain the deformation caused by earthquakes. <\/p>\n\n\n\n<p>Before an earthquake, the buildup of stress in the rocks on either side of a fault results in gradual deformation. Eventually, this deformation exceeds the frictional force holding the rocks together and sudden slip occurs along the fault. This releases the accumulated stress and the rocks on either side of the fault return to their original shape (elastic rebound) but are offset on either side of the fault.<\/p>\n\n\n<figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Movements_crust_BGS-2-150x150.jpg\" class=\"lazy-blur\" alt=\"Movements in the crust cause stress to build up.\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Movements_crust_BGS-2.jpg\" \/><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Over time stresses in the Earth build up (often caused by the slow movements of tectonic plates). At some point the stresses become so great that the Earth breaks. An earthquake rupture occurs and relieves some of the stresses (but generally not all). BGS \u00a9UKRI.<\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure>\n\n\n<h3 class=\"wp-block-heading\" id=\"fault\">Types of fault <\/h3>\n\n\n\n<p>There are three basic types of fault: normal, reverse and strike-slip. Certain types of fault are characteristic of the different plate boundaries, although often more than one type of fault occurs there. This can help us understand the relative movement of the plates and the type of deformation.<\/p>\n\n\n<div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Normal fault<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p>&nbsp;<\/p>\n<p><a href=\"http:\/\/https:\/\/www.youtube.com\/watch?v=vqWCpo-1jrU\"><iframe loading=\"lazy\" src=\"\/\/www.youtube.com\/embed\/vqWCpo-1jrU\" width=\"560\" height=\"314\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/a><\/p>\n<p>In a normal fault, the block above the fault moves down relative to the block below the fault. \u00a9 <a href=\"http:\/\/www.iris.edu\" target=\"_blank\" rel=\"noopener\">IRIS<\/a>. All rights reserved.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Reverse fault<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p><iframe loading=\"lazy\" src=\"\/\/www.youtube.com\/embed\/4b81nXSVA34\" width=\"560\" height=\"314\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>In a reverse fault, the block above the fault moves up relative to the block below the fault.\u00a0 \u00a9 <a href=\"http:\/\/www.iris.edu\" target=\"_blank\" rel=\"noopener\">IRIS<\/a>. All rights reserved.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div><div  class=\"accordions\">\n\t\t\t\t<div class=\"acc-wrap\">\n\t\t\t\t\t<button class=\"acc-top secondary-background icon-arrow button no-btn\"><span class=\"button-content\" tabindex=\"-1\">Strike-slip fault<\/span><\/button>\n\t\t\t\t\t<div class=\"acc-body sea-background-e\">\n\t\t\t\t\t\t<p><iframe loading=\"lazy\" src=\"\/\/www.youtube.com\/embed\/6wWcjNM_kRM\" width=\"560\" height=\"314\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>In a strike-slip fault, the movement of blocks along a fault is horizontal. \u00a9 <a href=\"http:\/\/www.iris.edu\" target=\"_blank\" rel=\"noopener\">IRIS<\/a>. All rights reserved.<\/p>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div>\n\n\n<p>During an earthquake, the rock on one side of the fault suddenly slips with respect to the other. The fault surface can be horizontal or vertical or some arbitrary angle in between. Faults are classified using the angle of the fault with respect to the surface (known as the dip) and the direction of slip along the fault. <\/p>\n\n\n\n<p>Faults that move along the direction of the dip plane are called dip-slip faults while strike-slip faults are classified as either right-lateral or left-lateral. Faults which show both dip-slip and strike-slip motion are known as oblique-slip faults.<\/p>\n\n\n<figure  class=\"img-wrap\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Fault_Types_BGS-150x150.jpg\" class=\"lazy-blur\" alt=\"Three types of fault\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Fault_Types_BGS.jpg\" \/><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Boundaries between tectonic plates are made up from a system of faults. Each type of boundary is associated with one of three basic types of fault, called normal, reverse and strike-slip faults. BGS \u00a9UKRI. All rights reserved.<\/p>\n<\/div>\n\t\t\t\t\t\n\t\t\t\t<\/figcaption><\/figure><\/div><\/div><\/div><\/section>\n\n\n\t\t\t\t\t<section   id=\"latest-content-4573-block_5e956f46512a4\" class=\"grid-section  primary-background   \" >\n\t\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row header-of-section\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t<h2>You may also be interested in<\/h2>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row grid-wrap\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/feature_homepage_p815563-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Ammonite p815563\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/feature_homepage_p815563.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\">Discovering Geology<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Discovering Geology introduces a range of geoscience topics to school-age students and learners of all ages.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_hazards_pexels_235807-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"lava flow - Pexels \/ Pixabay\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_hazards_pexels_235807.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\">Earth hazards<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>The Earth beneath our feet is constantly shifting and moving,  and violently with catastrophic and immediate results. Find out more about earth hazards.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2021\/06\/P680442_thumb-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"A white, four storey building in Izmit, Turkey, leans at a dangerous angle due to an earthquake. There is a road next to it with other buildings that are not affected.\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2021\/06\/P680442_thumb.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/\">Earthquakes<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Earthquakes are among the most deadly natural hazards. They strike without warning and many earthquake zones coincide with areas of high population density.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/where-do-earthquakes-occur\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/feature_worldearthquakes-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"World earthquakes\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/07\/feature_worldearthquakes.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/where-do-earthquakes-occur\/\">Where do earthquakes occur?<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Where earthquakes occur around the world and in the UK.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/where-do-earthquakes-occur\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-are-earthquakes-detected\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Detection_Feature_BGS-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Detection_Feature_BGS\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Detection_Feature_BGS.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-are-earthquakes-detected\/\">How are earthquakes detected?<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Seismometers are used to record the seismic waves produced by earthquakes. Relative arrival times of these waves is used to determine earthquake location.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-are-earthquakes-detected\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-do-earthquakes-affect-people\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Damaged_Building_Feature_USGS_JKNAKATA_Wikimedia-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Damaged building following earthquake\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Damaged_Building_Feature_USGS_JKNAKATA_Wikimedia.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-do-earthquakes-affect-people\/\">How do earthquakes affect people?<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>The extent of damage an earthquake causes depends not only on the magnitude of the earthquake, but also on local geology and on building techniques.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/how-do-earthquakes-affect-people\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\t\t","protected":false},"excerpt":{"rendered":"<p>The causes of earthquakes and the different types of tectonic boundaries and faults on which they usually occur.<\/p>\n","protected":false},"author":2,"featured_media":27611,"parent":25266,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"on","_relevanssi_pin_keywords":"what causes earthquakes, causes of earthquakes","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"33925,8391,37440,34185,9908,6297","_relevanssi_noindex_reason":"","footnotes":""},"tags":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>What causes earthquakes? - British Geological Survey<\/title>\n<meta name=\"description\" content=\"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What causes earthquakes? - British Geological Survey\" \/>\n<meta property=\"og:description\" content=\"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\" \/>\n<meta property=\"og:site_name\" content=\"British Geological Survey\" \/>\n<meta property=\"article:modified_time\" content=\"2021-06-10T11:51:18+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"640\" \/>\n\t<meta property=\"og:image:height\" content=\"430\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\",\"url\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\",\"name\":\"What causes earthquakes? - British Geological Survey\",\"isPartOf\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg\",\"datePublished\":\"2020-04-14T08:06:37+00:00\",\"dateModified\":\"2021-06-10T11:51:18+00:00\",\"description\":\"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %\",\"breadcrumb\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#breadcrumb\"},\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage\",\"url\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg\",\"contentUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg\",\"width\":640,\"height\":430,\"caption\":\"A convergent, or destructive, boundary showing subduction of an oceanic plate under a continental plate. BGS \u00a9UKRI. All rights reserved.\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.bgs.ac.uk\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Discovering Geology\",\"item\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Earth hazards\",\"item\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\"},{\"@type\":\"ListItem\",\"position\":4,\"name\":\"Earthquakes\",\"item\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/\"},{\"@type\":\"ListItem\",\"position\":5,\"name\":\"What causes earthquakes?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#website\",\"url\":\"https:\/\/www.bgs.ac.uk\/\",\"name\":\"British Geological Survey\",\"description\":\"World-leading geological solutions\",\"publisher\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.bgs.ac.uk\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-GB\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#organization\",\"name\":\"British Geological Survey\",\"url\":\"https:\/\/www.bgs.ac.uk\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png\",\"contentUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png\",\"width\":250,\"height\":104,\"caption\":\"British Geological Survey\"},\"image\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"What causes earthquakes? - British Geological Survey","description":"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/","og_locale":"en_GB","og_type":"article","og_title":"What causes earthquakes? - British Geological Survey","og_description":"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %","og_url":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/","og_site_name":"British Geological Survey","article_modified_time":"2021-06-10T11:51:18+00:00","og_image":[{"width":640,"height":430,"url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"Estimated reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/","url":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/","name":"What causes earthquakes? - British Geological Survey","isPartOf":{"@id":"https:\/\/www.bgs.ac.uk\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage"},"image":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage"},"thumbnailUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg","datePublished":"2020-04-14T08:06:37+00:00","dateModified":"2021-06-10T11:51:18+00:00","description":"Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Most earthquakes are associated with tectonic plate boundaries. %","breadcrumb":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#primaryimage","url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg","contentUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Convergent_boundary_feature_BGS.jpg","width":640,"height":430,"caption":"A convergent, or destructive, boundary showing subduction of an oceanic plate under a continental plate. BGS \u00a9UKRI. All rights reserved."},{"@type":"BreadcrumbList","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/what-causes-earthquakes\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.bgs.ac.uk\/"},{"@type":"ListItem","position":2,"name":"Discovering Geology","item":"https:\/\/www.bgs.ac.uk\/discovering-geology\/"},{"@type":"ListItem","position":3,"name":"Earth hazards","item":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/"},{"@type":"ListItem","position":4,"name":"Earthquakes","item":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/"},{"@type":"ListItem","position":5,"name":"What causes earthquakes?"}]},{"@type":"WebSite","@id":"https:\/\/www.bgs.ac.uk\/#website","url":"https:\/\/www.bgs.ac.uk\/","name":"British Geological Survey","description":"World-leading geological solutions","publisher":{"@id":"https:\/\/www.bgs.ac.uk\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.bgs.ac.uk\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-GB"},{"@type":"Organization","@id":"https:\/\/www.bgs.ac.uk\/#organization","name":"British Geological Survey","url":"https:\/\/www.bgs.ac.uk\/","logo":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/","url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png","contentUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png","width":250,"height":104,"caption":"British Geological Survey"},"image":{"@id":"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/"}}]}},"_links":{"self":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/26451"}],"collection":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/comments?post=26451"}],"version-history":[{"count":83,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/26451\/revisions"}],"predecessor-version":[{"id":73927,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/26451\/revisions\/73927"}],"up":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/25266"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/media\/27611"}],"wp:attachment":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/media?parent=26451"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/tags?post=26451"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}