{"id":2098,"date":"2016-06-06T21:32:08","date_gmt":"2016-06-06T21:32:08","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/geologyxwaymakerxmaster\/?post_type=chapter&#038;p=2098"},"modified":"2023-06-28T18:44:00","modified_gmt":"2023-06-28T18:44:00","slug":"outcome-monitoring-volcanoes","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/chapter\/outcome-monitoring-volcanoes\/","title":{"raw":"Monitoring Volcanoes","rendered":"Monitoring Volcanoes"},"content":{"raw":"<h2>Identify the various methods used to monitor volcanic activity<\/h2>\r\nThere are several different ways to monitor volcanoes.\u00a0Let's take a look at some of these different methods.\r\n<div class=\"textbox learning-objectives\">\r\n<h3>What You\u2019ll Learn to Do<\/h3>\r\n<ul>\r\n \t<li>Identify the six most important signs of an imminent volcanic eruption.<\/li>\r\n \t<li>Identify tools that can aid in monitoring volcanoes and actions that should be taken.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Signs of an Eruption<\/h2>\r\nIn 2005 USGS geologist Chris Newhall made a list of the six most important signs of an imminent volcanic eruption. They are as follows:\r\n<ol>\r\n \t<li><em>Gas leaks<\/em> \u2014 the release of gases (mostly H<sub>2<\/sub>O, CO<sub>2<\/sub>, and SO<sub>2<\/sub>) from the magma into the atmosphere through cracks in the overlying rock<\/li>\r\n \t<li><em>Bit of a bulge<\/em> \u2014 the deformation of part of the volcano, indicating that a magma chamber at depth is swelling or becoming more pressurized<\/li>\r\n \t<li><em>Getting shaky<\/em> \u2014 many (hundreds to thousands) of small earthquakes, indicating that magma is on the move. The quakes may be the result of the magma forcing the surrounding rocks to crack, or a harmonic vibration that is evidence of magmatic fluids moving underground.<\/li>\r\n \t<li><em>Dropping fast<\/em> \u2014 a sudden decrease in the rate of seismicity, which may indicate that magma has stalled, which could mean that something is about to give way<\/li>\r\n \t<li><em>Big bump<\/em> \u2014 a pronounced bulge on the side of the volcano (like the one at Mt. St. Helens in 1980), which may indicate that magma has moved close to surface<\/li>\r\n \t<li><em>Blowing off steam<\/em> \u2014 steam eruptions (a.k.a. <strong>phreatic<\/strong> <strong>eruptions<\/strong>) that happen when magma near the surface heats groundwater to the boiling point. The water eventually explodes, sending fragments of the overlying rock far into the air.<\/li>\r\n<\/ol>\r\n<h2>Tools to Monitor Volcanoes<\/h2>\r\nHere is\u00a0a list of the equipment we should have and the actions we can take to monitor a volcano and predict when it might erupt.\r\n<h3>Assessing Seismicity<\/h3>\r\n[caption id=\"attachment_2200\" align=\"alignright\" width=\"450\"]<img class=\"wp-image-2200\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/115\/2016\/06\/06225110\/seismometer-1024x573.jpg\" alt=\"Three scientists standing by a seismometer\" width=\"450\" height=\"252\" \/> Figure 1. A seismometer installed in 2007 in the vicinity of the Nazco Cone, B.C. [photo Cathie Hickson, used with permission][\/caption]The simplest and cheapest way to monitor a volcano is with seismometers. In an area with several volcanoes that have the potential to erupt (e.g., the Squamish-Pemberton area), a few well-placed seismometers can provide us with an early warning that something is changing beneath one of the volcanoes, and that we need to take a closer look. There are currently enough seismometers in the Lower Mainland and on Vancouver Island to provide this information.[footnote]See: <a href=\"http:\/\/www.earthquakescanada.nrcan.gc.ca\/stndon\/CNSN-RNSC\/stnbook-cahierstn\/index-eng.php?tpl_sorting=map&amp;CHIS_SZ=west\" target=\"_blank\" rel=\"noopener\">http:\/\/www.earthquakescanada.nrcan.gc.ca<\/a>[\/footnote]\r\n\r\nIf there is seismic evidence that a volcano is coming to life, more seismometers should be placed in locations within a few tens of kilometers of the source of the activity (Figure 1). This will allow geologists to determine the exact location and depth of the seismic activity so that they can see where the magma is moving.\r\n<h3>Detecting Gases<\/h3>\r\nWater vapor quickly turns into clouds of liquid water droplets and is relatively easy to detect just by looking, but CO<sub>2<\/sub> and SO<sub>2<\/sub> are not as obvious. It\u2019s important to be able to monitor changes in the composition of volcanic gases, and we need instruments to do that. Some can be monitored from a distance (from the ground or even from the air) using infrared devices, but to obtain more accurate data, we need to sample the air and do chemical analysis. This can be achieved with instruments placed on the ground close to the source of the gases, or by collecting samples of the air and analyzing them in a lab.\r\n<h3>Measuring Deformation<\/h3>\r\n[caption id=\"attachment_2202\" align=\"alignright\" width=\"450\"]<img class=\"wp-image-2202\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/115\/2016\/06\/06225217\/Hualalai-volcano1.jpg\" alt=\"Photograph of a GPS unit installed at Hualalai volcano, Hawaii\" width=\"450\" height=\"375\" \/> Figure 2. A GPS unit installed at Hualalai volcano, Hawaii. The dish-shaped antenna on the right is the GPS receiver. The antenna on the left is for communication with a base station. [from USGS at: http:\/\/hvo.wr.usgs.gov\/volcanowatch\/view.php?id=173][\/caption]There are two main ways to measure ground deformation at a volcano. One is known as a <strong>tiltmeter<\/strong>, which is a sensitive three-directional level that can sense small changes in the tilt of the ground at a specific location. Another is through the use of GPS (global positioning system) technology (Figure 2). GPS is more effective than a tiltmeter because it provides information on how far the ground has actually moved \u2014 east-west, north-south, and up-down.\r\n\r\nBy combining information from these types of sources, along with careful observations made on the ground and from the air, and a thorough knowledge of how volcanoes work, geologists can get a good idea of the potential for a volcano to erupt in the near future (months to weeks, but not days). They can then make recommendations to authorities about the need for evacuations and restricting transportation corridors. Our ability to predict volcanic eruptions has increased dramatically in recent decades because of advances in our understanding of how volcanoes behave and in monitoring technology. Providing that careful work is done, there is no longer a large risk of surprise eruptions, and providing that public warnings are issued and heeded, it is less and less likely that thousands will die from sector collapse, pyroclastic flows, ash falls, or lahars. Indirect hazards are still very real, however, and we can expect the next eruption like the one at Laki in 1783 to take an even greater toll than it did then, especially since there are now roughly eight times as many people on Earth.\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Think about It:\u00a0<strong>Volcano Alert!<\/strong><\/h3>\r\nYou\u2019re the chief volcanologist for the Geological Survey of Canada (GSC), based in Vancouver. At 10:30 a.m. on a Tuesday, you receive a report from a seismologist at the GSC in Sidney saying that there has been a sudden increase in the number of small earthquakes in the vicinity of Mt. Garibaldi. You have two technicians available, access to some monitoring equipment, and a four-wheel-drive vehicle. At noon, you meet with your technicians and a couple of other geologists. By the end of the day, you need to have a plan to implement, starting tomorrow morning, and a statement to release to the press. What should your first day\u2019s fieldwork include? What should you say later today in your press release?\r\n\r\n<\/div>\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Check Your Understanding<\/h3>\r\nWhich of the following is a possible sign of an impending eruption?\r\n<ul>\r\n \t<li>a volcano getting larger in size<\/li>\r\n \t<li>lots of earthquakes around and under the volcano<\/li>\r\n \t<li>average temperatures in the area increasing<\/li>\r\n<\/ul>\r\n<details><summary>Show Answer<\/summary>lots of earthquakes around and under the volcano\r\n\r\n<\/details><\/div>\r\n","rendered":"<h2>Identify the various methods used to monitor volcanic activity<\/h2>\n<p>There are several different ways to monitor volcanoes.\u00a0Let&#8217;s take a look at some of these different methods.<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>What You\u2019ll Learn to Do<\/h3>\n<ul>\n<li>Identify the six most important signs of an imminent volcanic eruption.<\/li>\n<li>Identify tools that can aid in monitoring volcanoes and actions that should be taken.<\/li>\n<\/ul>\n<\/div>\n<h2>Signs of an Eruption<\/h2>\n<p>In 2005 USGS geologist Chris Newhall made a list of the six most important signs of an imminent volcanic eruption. They are as follows:<\/p>\n<ol>\n<li><em>Gas leaks<\/em> \u2014 the release of gases (mostly H<sub>2<\/sub>O, CO<sub>2<\/sub>, and SO<sub>2<\/sub>) from the magma into the atmosphere through cracks in the overlying rock<\/li>\n<li><em>Bit of a bulge<\/em> \u2014 the deformation of part of the volcano, indicating that a magma chamber at depth is swelling or becoming more pressurized<\/li>\n<li><em>Getting shaky<\/em> \u2014 many (hundreds to thousands) of small earthquakes, indicating that magma is on the move. The quakes may be the result of the magma forcing the surrounding rocks to crack, or a harmonic vibration that is evidence of magmatic fluids moving underground.<\/li>\n<li><em>Dropping fast<\/em> \u2014 a sudden decrease in the rate of seismicity, which may indicate that magma has stalled, which could mean that something is about to give way<\/li>\n<li><em>Big bump<\/em> \u2014 a pronounced bulge on the side of the volcano (like the one at Mt. St. Helens in 1980), which may indicate that magma has moved close to surface<\/li>\n<li><em>Blowing off steam<\/em> \u2014 steam eruptions (a.k.a. <strong>phreatic<\/strong> <strong>eruptions<\/strong>) that happen when magma near the surface heats groundwater to the boiling point. The water eventually explodes, sending fragments of the overlying rock far into the air.<\/li>\n<\/ol>\n<h2>Tools to Monitor Volcanoes<\/h2>\n<p>Here is\u00a0a list of the equipment we should have and the actions we can take to monitor a volcano and predict when it might erupt.<\/p>\n<h3>Assessing Seismicity<\/h3>\n<div id=\"attachment_2200\" style=\"width: 460px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2200\" class=\"wp-image-2200\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/115\/2016\/06\/06225110\/seismometer-1024x573.jpg\" alt=\"Three scientists standing by a seismometer\" width=\"450\" height=\"252\" \/><\/p>\n<p id=\"caption-attachment-2200\" class=\"wp-caption-text\">Figure 1. A seismometer installed in 2007 in the vicinity of the Nazco Cone, B.C. [photo Cathie Hickson, used with permission]<\/p>\n<\/div>\n<p>The simplest and cheapest way to monitor a volcano is with seismometers. In an area with several volcanoes that have the potential to erupt (e.g., the Squamish-Pemberton area), a few well-placed seismometers can provide us with an early warning that something is changing beneath one of the volcanoes, and that we need to take a closer look. There are currently enough seismometers in the Lower Mainland and on Vancouver Island to provide this information.<a class=\"footnote\" title=\"See: http:\/\/www.earthquakescanada.nrcan.gc.ca\" id=\"return-footnote-2098-1\" href=\"#footnote-2098-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a><\/p>\n<p>If there is seismic evidence that a volcano is coming to life, more seismometers should be placed in locations within a few tens of kilometers of the source of the activity (Figure 1). This will allow geologists to determine the exact location and depth of the seismic activity so that they can see where the magma is moving.<\/p>\n<h3>Detecting Gases<\/h3>\n<p>Water vapor quickly turns into clouds of liquid water droplets and is relatively easy to detect just by looking, but CO<sub>2<\/sub> and SO<sub>2<\/sub> are not as obvious. It\u2019s important to be able to monitor changes in the composition of volcanic gases, and we need instruments to do that. Some can be monitored from a distance (from the ground or even from the air) using infrared devices, but to obtain more accurate data, we need to sample the air and do chemical analysis. This can be achieved with instruments placed on the ground close to the source of the gases, or by collecting samples of the air and analyzing them in a lab.<\/p>\n<h3>Measuring Deformation<\/h3>\n<div id=\"attachment_2202\" style=\"width: 460px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2202\" class=\"wp-image-2202\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/115\/2016\/06\/06225217\/Hualalai-volcano1.jpg\" alt=\"Photograph of a GPS unit installed at Hualalai volcano, Hawaii\" width=\"450\" height=\"375\" \/><\/p>\n<p id=\"caption-attachment-2202\" class=\"wp-caption-text\">Figure 2. A GPS unit installed at Hualalai volcano, Hawaii. The dish-shaped antenna on the right is the GPS receiver. The antenna on the left is for communication with a base station. [from USGS at: http:\/\/hvo.wr.usgs.gov\/volcanowatch\/view.php?id=173]<\/p>\n<\/div>\n<p>There are two main ways to measure ground deformation at a volcano. One is known as a <strong>tiltmeter<\/strong>, which is a sensitive three-directional level that can sense small changes in the tilt of the ground at a specific location. Another is through the use of GPS (global positioning system) technology (Figure 2). GPS is more effective than a tiltmeter because it provides information on how far the ground has actually moved \u2014 east-west, north-south, and up-down.<\/p>\n<p>By combining information from these types of sources, along with careful observations made on the ground and from the air, and a thorough knowledge of how volcanoes work, geologists can get a good idea of the potential for a volcano to erupt in the near future (months to weeks, but not days). They can then make recommendations to authorities about the need for evacuations and restricting transportation corridors. Our ability to predict volcanic eruptions has increased dramatically in recent decades because of advances in our understanding of how volcanoes behave and in monitoring technology. Providing that careful work is done, there is no longer a large risk of surprise eruptions, and providing that public warnings are issued and heeded, it is less and less likely that thousands will die from sector collapse, pyroclastic flows, ash falls, or lahars. Indirect hazards are still very real, however, and we can expect the next eruption like the one at Laki in 1783 to take an even greater toll than it did then, especially since there are now roughly eight times as many people on Earth.<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Think about It:\u00a0<strong>Volcano Alert!<\/strong><\/h3>\n<p>You\u2019re the chief volcanologist for the Geological Survey of Canada (GSC), based in Vancouver. At 10:30 a.m. on a Tuesday, you receive a report from a seismologist at the GSC in Sidney saying that there has been a sudden increase in the number of small earthquakes in the vicinity of Mt. Garibaldi. You have two technicians available, access to some monitoring equipment, and a four-wheel-drive vehicle. At noon, you meet with your technicians and a couple of other geologists. By the end of the day, you need to have a plan to implement, starting tomorrow morning, and a statement to release to the press. What should your first day\u2019s fieldwork include? What should you say later today in your press release?<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Check Your Understanding<\/h3>\n<p>Which of the following is a possible sign of an impending eruption?<\/p>\n<ul>\n<li>a volcano getting larger in size<\/li>\n<li>lots of earthquakes around and under the volcano<\/li>\n<li>average temperatures in the area increasing<\/li>\n<\/ul>\n<details>\n<summary>Show Answer<\/summary>\n<p>lots of earthquakes around and under the volcano<\/p>\n<\/details>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2098\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Introduction to Monitoring Volcanoes. <strong>Authored by<\/strong>: Kimberly Schulte and Lumen Learning. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>4.5 Monitoring Volcanoes and Predicting Eruptions. <strong>Authored by<\/strong>: Steven Earle. <strong>Provided by<\/strong>: BC Campus. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/opentextbc.ca\/geology\/chapter\/4-5-monitoring-volcanoes-and-predicting-eruptions\/\">https:\/\/opentextbc.ca\/geology\/chapter\/4-5-monitoring-volcanoes-and-predicting-eruptions\/<\/a>. <strong>Project<\/strong>: Physical Geology. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section><hr class=\"before-footnotes clear\" \/><div class=\"footnotes\"><ol><li id=\"footnote-2098-1\">See: <a href=\"http:\/\/www.earthquakescanada.nrcan.gc.ca\/stndon\/CNSN-RNSC\/stnbook-cahierstn\/index-eng.php?tpl_sorting=map&amp;CHIS_SZ=west\" target=\"_blank\" rel=\"noopener\">http:\/\/www.earthquakescanada.nrcan.gc.ca<\/a> <a href=\"#return-footnote-2098-1\" class=\"return-footnote\" aria-label=\"Return to footnote 1\">&crarr;<\/a><\/li><\/ol><\/div>","protected":false},"author":17,"menu_order":7,"template":"","meta":{"_candela_citation":"[{\"type\":\"original\",\"description\":\"Introduction to Monitoring Volcanoes\",\"author\":\"Kimberly Schulte and Lumen Learning\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"4.5 Monitoring Volcanoes and Predicting Eruptions\",\"author\":\"Steven Earle\",\"organization\":\"BC 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