Part 4: Volcanic Hazards & Monitoring “Normal” view has a Notes panel below with lecture notes and links to video lectures, activities, or web sites. “Slide Show” view has animated elements that pop up on clicking Video & animations were removed to increase speed. Download information is in the Notes panel in Normal view. If you got this slide show on a DVD, the related animations will also be in a folder associated with the PowerPoint. Modify slide show liberally for your own needs! Excellent additional information and teaching materials on volcanoes can be found at: US Geological Survey - http://volcanoes.usgs.gov/ Cascade Volcanic Observatory (of USGS) – http://volcanoes.usgs.gov/observatories/cvo/ UNAVCO - http://www.unavco.org/edu_outreach/resources/resources.html (Find: volcano) Slide show prepared by Dr. Beth Pratt-Sitaula (Central Washington University) and Jenda Johnson (IRIS).

Volcanoes are… An opening on the planet’s surface where molten rock, ash, or gases escape from below On this and other slides throughout the show (marked by a “star”) components of the text or images are added incrementally using PowerPoint’s animation function. Many people have the image that volcanoes are all tall, steep-sided, red-magma-spewing, edifices. The slides show starts with trying to break down these stereotypes. After that it progresses to explaining the main factors controlling the development of different types of volcanoes. Finally, the talk describes measures related to volcanic monitoring and hazard mitigation. There is not a single absolutely agreed upon definition of a volcano, but this one satisfies most people. Aleutian Islands, AK; International Space Station photo http://earthquake.usgs.gov/ monitoring/anss/regions/hi/

Volcano Prior Knowledge Survey TRUE/FALSE –> thumbs up OR down 1. Volcanoes are steep-sided and ooze hot runny lava In order to build up a steep-sided mountain, the lava needs to not flow too easily. Lava that flows very easily runs a long way and makes broad low-angle mountains such as Hawaii. There will be more images to address this issue later in the talk. FALSE - “Hot runny” volcanoes are mostly flat or shield like

It is not at all surprising that people think steep volcanoes spew hot running lava because, however inaccurate, that is the image that is usually presented by the media*. *Hollywood is not a recommended source for accurate geologic information http://www.imdb.com/media/rm1327600128/tt0445548

Volcano Prior Knowledge Survey TRUE/FALSE –> thumbs up OR down 2. The biggest eruptions flatten topography. The talk will give specific examples of each these types of eruptions later. Flood basalts can fill in topography leading very flat areas – examples include Columbia Plateau in the Pacific Northwest of the USA and the Siberian Traps in Siberia, Russia. Mountains can be completely obliterated in caldera-forming eruptions. Yellowstone (National Park in Wyoming) used to have much higher mountains before several large caldera eruptions. Crater Lake (National Park in Oregon) used to much taller too – until about 6000 years ago when the top was blown off. Even Mt St Helens (National Park in Washington) was taller before its 1980 eruption. The eruptions that build topography (and lead to nice steep mountains such as Mt Rainier and Mt Fuji) tend to be more incremental with layers of more viscous (not super “runny”) lava flows alternating with ash deposits of various sorts. TRUE – largest volume eruptions lead to flood basalt plateaus; most explosive eruptions lead to mountains getting blown to bits

So while it would be unfortunate if urban areas around the world were simultaneously impinged on by stratovolcanoes* (not to mention unlikely), caldera-forming eruptions or flood basalts would be much more worrisome. *Hollywood is not a recommended source for accurate geologic information http://www.imdb.com/media/rm1327600128/tt0445548

Volcano Prior Knowledge Survey TRUE/FALSE –> thumbs up OR down 3. Magma chambers are…big chambers of liquid rock FALSE - Magma “chambers” form when lava is injected in cracks and crevasses and pushes against existing rock. They are usually more of a plumbing system than a chamber. The big red “balloon” of liquid magma usually shown in images (even in text books) is pretty inaccurate. Based on our best evidence from the rock record and geophysics analysis of the area under volcanoes, magma “chambers” are actually a complex plumbing system of magma “conduits”. Certainly some larger chambers exist, but they are probably not as extensive as usually depicted. GELATIN MODEL OF MAGMA INTRUSION CLASSROOM ACTIVITY does a great job illustrating the variety of different intrusive structures that can lie below a volcano. URL http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/GelatinModelOfMagmaIntrusion__LessonPlan_TOTLE.pdf VIDEO OF GELATIN MODEL OF MAGMA INTRUSION: Roger Groom, Mt Tabor Middle School, demonstrates how to set up the Gelatin Model of Magma Intrusion. URL http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/Videos/GelatinVolcano_GroomDEMO.mov

Unfortunately, many textbooks show inaccurate pictures of magma chambers and volcanoes. Magma chamber are almost always shown as these big red globs.

SHOW ANIMATION “Mesozoic Subduction” from URL below. This animation can be downloaded from http://emvc.geol.ucsb.edu/2_infopgs/IP1GTect/cSubduction.html This animation shows many things about subduction, but it is being shown as part of this slide show because it is one of the few animations that accurately depicts the incremental formation of a batholith (large intrusive rock body – often granite) and how this lower magma feeds conduits that bring liquid rock to the surface. SHOW ANIMATION “Mesozoic Subduction” from URL below. http://emvc.geol.ucsb.edu/2_infopgs/IP1GTect/cSubduction.html

Some volcano stats How many active volcanoes on Earth? How many volcanoes erupt per year? How many people are killed by volcanoes? ~1,500 active volcanoes ~60 volcanoes erupt per year Info from: 1. http://www.volcano.si.edu/faq.cfm#q3 “Active” means eruptions in the Holocene (last ~10,000 years). 2. http://www.volcano.si.edu/faq.cfm#q3 3. http://www.volcanolive.com/fatalities.html Four causes resulted in 91% of the fatalities - famine and epidemic disease (30%), pyroclastic flows (27%), lahars (17%), and tsunamis (17%). ~200,000 in the last 200 years

Where does molten rock come from? THE MANTLE IS NOT LIQUID. The idea of a liquid mantle is a very persistent misconception that people have related to geological phenomena. The mantle is SOLID but it is hot and does flow very gradually around in big convection currents (plate tectonic movement). Most solids deform when they are hot and have a shear force exerted on them. They just deform at different rates depending on the substance and the temperature. BUT by definition, volcanoes are places that liquid rock makes it to the surface of the Earth, so this liquid rock must form somewhere. Where does it form and why? Modified from USGS Graphics MANTLE IS NOT LIQUID!!

Where do volcanoes form? In thinking about why molten rock forms, it is helpful to start by thinking about where volcanoes form. Do the locations of volcanoes give us any indication of how the magma forms? CLASSROOM ACTIVITY: The Seismic Eruption software allows users to explore the relationships between plate tectonics, earthquakes, and volcanoes. A student worksheet can be found on the TOTLE web site at: http://multimedia2.up.edu/Physics/TOLE/Plates&Earthquakes/LessonPlans/SeismicEruptionPrgm.doc Subduction zones “Hot spots” Mid-ocean ridges Continental rift zones

Rocks melt under certain circumstances Heating Decompression Reducing melting temp by adding water Heating: Of course it makes sense that additional heating can cause a solid to melt. However, this is NOT a significant player in how molten rock is on Earth! Decompression melting: If a substance is near its melting point and then the pressure on it is reduced, it can lead to melting. This is the main mechanism behind melt formation at mid-ocean ridges, hot spots, and continental rift zones. In all those situations material is moving upwards relatively rapidly and thus experiencing pressure reduction more quickly than temperature cooling. It can be a little hard to comprehend this mechanism because we do not tend to experience rapid changes in pressure in our everyday lives. One analogy (using boiling instead of melting) might help... Most people know that water boils at a lower temperature at higher altitudes (the reason one needs to cook pasta for longer when camping up in high mountains). Thus if you have a pot of water fairly close to boiling at regular sea level atmospheric pressure and you took it up in an airplane or did something else to reduce the pressure, it would start to boil. Same idea with hot mantle rocks  bring them to a lower pressure level in the Earth and they melt. Adding water: In subduction zones, water from marine sediments and oceanic crustal rocks on the down-going plate changes the chemistry of the overlying mantle material, depressing the melting temperature and leading to melting. In all cases, the volume of molten rock is miniscule compared to the mass of the crust and mantle as a whole.

Types of Volcanoes Flood Basalts Millions km3 of horizontal basalt layers Types of Volcanoes A variety of different types of volcanic structures and eruptions styles occurs. So the question becomes…WHY THE VARIETY? Shown here are the main types of terrestrial volcanoes. Columbia Flood Basalts Photo by Thor Thordarsson

Why do different magmas behave differently & make very different volcanoes? VISCOSITY VOLATILES VOLUME “3 Vs” WATER CARBON DIOXIDE Sulfur dioxide Hydrogen sulfide There are three main characteristics of a magma which determine the type of eruptions which it could lead to. These have conveniently been called the “three Vs” because to help with remembering them. VISCOSITY is determined by the chemistry of the molten rock (more on that in the next slides). VOLATILES are gases within the melt with water vapor and carbon dioxide being the most abundant. The VOLUME of the magma reservoir in also an important determiner of the ultimate type of eruption.

Viscosity determines: The flow rate of magma VOLATILE trapping Viscosity determines the rate at which the magma/lava will flow and thus how far it can travel. It also determines how effective the magma will be at trapping volatiles. A low viscosity magma will allow volatiles to escape non-explosively whereas a high viscosity magma will trap them allowing pressure to build and developing the potential for an explosive eruption. Thinking in terms of the “Coke bottle” index – a low viscosity magma is like a Coke with the lid off. The CO2 just gradually and seeps out without frothing over (non-explosive eruption). A high viscosity magma is like Coke with the lid on being shaken. When you them remove the lid, the Coke foams over all over the place (explosive eruption). vs

Viscosity depends on chemical composition LESS SILICA (=quartz=SiO2) MORE iron & magnesium LOTS O’ SILICA What determines the viscosity of the lava? Chemistry! CLASSROOM ACTIVITIES ON LAVA VISCOSITY: Modeling Lava Viscosity Demonstration can be found at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/ModelingLavaViscosity_LessonPlan_TOTLE.pdf Supporting Table of Volcanic Eruption Styles is at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/LavaViscosity_TABLE4Students-blank.doc Answers for Table of Volcanic Eruption Styles is at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/LavaViscocity_Demo_Table4TEACHERS.doc Iron- and magnesium-rich (silica-poor) magmas melt at a higher temperature and have a low viscosity (flow easily). Thus they can flow for long distances and any volatiles within them usually bubble out easily without causing a major explosion. Typical resulting rock type is basalt. Another term you might hear for iron/magnesium-rich rocks is “mafic”. Extremely silica-poor (iron/magnesium-rich) rocks are “ultramafic.” Silica-rich magmas have a lower melting point and are quite viscous. They are higher resistant to flow and trap volatiles so that pressure builds creating the potential for highly explosive eruptions. The resulting rocks of very silica-rich eruptions are called rhyolites. Another term for silica-rich rocks is “felsic.” The most common and silica-rich mineral is “quartz” – with the mineral with the chemical composition of SiO2. ADDITIONAL INFORMATION: Mantle rocks are iron- and magnesium-rich. Whenever molten mantle makes it all the way to the surface without significant interaction with the crustal rocks, the eruptions are basaltic (or even ultramafic). Mid-ocean ridge eruptions are non-explosive as mantle-derived melt is formed very close to the surface and easily releases volatiles as it moves the short distance to the surface. However, if magma travels through a significant distance of crust (especially the more silica-rich continental crust) its composition changes. This can happen in two ways: 1) as the melt cools, the iron/magnesium components preferentially crystallize out of the melt into iron/magnesium-rich minerals leaving behind an increasingly rhyolitic (silica-rich) magma and 2) as the magma rises through the crust, it can melt some of the crustal rocks incorporating that material into the magma. The minerals with the lowest melting temperatures (and thus the ones that get incorporated the most easily) are silica-rich ones such as quartz. Again this leads to an increasingly rhyolitic magma. If you want to learn more about this process, you can look up “Bowen’s reaction series” in any geology text book or online. http://volcanoes.usgs.gov/images/pglossary/VolRocks.php

Types of Volcanoes Flood Basalts Millions km3 of horizontal basalt layers Types of Volcanoes Next we will work : 1) the “3V” characteristics which lead to each of these types of volcanic edifices; 2) the primary hazards associated with each; and 3) examples of each (if available) in the Pacific NW. More details on the hazards will also be given later in the lecture. Columbia Flood Basalts Photo by Thor Thordarsson

Flood basalts Extremely low viscosity Few volatiles (non-explosive) GENERAL CHARACTERISTICS – Flood basalt provinces are found in many places around the world, both on continents and under the ocean. The magmas have very low viscosity which allows the lava to travel 100’s of kilometers after eruption and allows passive, non-explosive release of volatiles (open bottle on the Coke Index). The volumes associated with these eruptions dwarf other eruptions by orders of magnitude. http://www.fas.org/irp/imint/docs/rst/Sect17/Sect17_3.html Extremely low viscosity Few volatiles (non-explosive) Very very large volume

Flood basalts - HAZARDS HAZARDS – theoretically, lava flows covering your entire state and huge release of green house gasses. However, no flood basalts are currently erupting. If any get going, we would have thousands of years to move people out of the way before the Really Big part of the eruptions get going. The main current hazard is falling asleep at the wheel due to geologic boredom when transiting a flood basalt province with 100’s of kilometers of basalt-basalt-basalt. Unless you really like basalt, in which case you might drive off the road in the excitement of rubbernecking. http://www.fas.org/irp/imint/docs/rst/Sect17/Sect17_3.html Bury your state in lava Huge green house gas release Geologic ennui (if you find basalt dull) Not a current hazard

Columbia River Flood Basalts Thor Thordarsson Over 300 separate flows averaging 580 km3 EACH 3.5 km thick in places Erupted 17.5-6 Ma ~90% erupted 16-15 Ma PACIFIC NORTHWEST – The Pacific NW has the best example of flood basalts in North America – the Columbia Flood Basalts. They erupted from fissures along the northern Oregon-Idaho border and blanket large regions of Washington and Oregon. Although various minor flows occurred over more than 10 million years, the vast majority came within a single million year span of 16.5-15.6 million years ago. These flows are called the Grande Ronde flows and are depicted on this image in light blue. They contain 85-90% of the entire volume of flows. The earlier flows sources further to the south and lava pooled in SE Oregon (Steen flows). Later and larger flows came from fissures a bit further north and flowed across what is now the Snake and Lower Columbia River basins. **It is fun to note where the topographic low areas must have been 15 million years ago! Some things have not changed so much since then. http://geosphere.gsapubs.org/content/4/3/480.full.pdf+html

Shield Volcanoes Low viscosity Few volatiles (non-explosive) Large volume GENERAL CHARACTERISTICS – Shield volcanoes also form from basaltic (low viscosity) magmas. The magmas are somewhat more viscous than in flood basalts, so the flows do not go quite as far and instead create very broad low-angle mounds that can be more than 100 km in diameter. The shape is reminiscent of a warrior’s shield laid flat – hence the name. The most famous shield volcano is probably Mauna Loa, Hawaii (formed from a hotspot punching through oceanic crust); but they can form in other settings, including subduction arcs. Due to the low viscosity, the volatiles (and explosivity) are low. The volume of a given eruption can vary from moderate to large but overall the volcanic edifice is the largest found except for flood basalts. Mauna Loa, Hawaii USGS

Shield Volcanoes - HAZARDS Lava flows Volcanic gasses (esp. CO2) Not hugely hazardous HAZARDS – Lava flows can enter developed areas destroying property and infrastructure. They seldom cause deaths because there is usually enough warning time to move people and animals out of the way. Volcanic gases can cause death through asphyxiation (displacing oxygen with carbon dioxide) with or without a concurrent eruption. PACIFIC NORTHEWEST – Medicine Lake Volcano, CA and Newberry Volcano, OR are the two shield volcanoes in this region. Although it is shorter than most other volcanoes, Medicine Lake has the largest volume of any volcano in the Pacific Northwest. Medicine Lake Volcano, CA USGS

Cinder cone (or scoria cone) Moderate viscosity Some volatiles Small volume Lava Butte, OR GENERAL CHARACTERISTICS – Cinder cones are found on the sides of larger shield or stratovolcanoes or as stand-alone features in a larger volcanically active region. They are seldom even a kilometer in diameter. They are generated when there are sufficient magma viscosity and volatiles to eject volcanic “popcorn” from a vent. However, due to the small volume of magma in the secondary conduits from which cinder cones erupt, they are not highly explosive or extensive. HAZARDS – Similar to lava flows, cinder cones are not highly hazardous to human life. There have been occasions when one started suddenly and forced homes and infrastructure to be abandoned, but they generally do not result in loss of life. PACIFIC NORTHWEST – Cinder cones can be found associated with pretty much every volcanic center in the Cascades. Some of the most visually obvious and numerous examples can be found in central Oregon near Bend associated with the Newberry Volcano. The one pictured here is near down town Bend, OR – Lava Butte cinder cone. ~600 m Image released to public domain by Q Myers (English Wikipedia)

Stratovolcano Mod–high viscosity Few-many volatiles (mod-very explosive) Mod-large volume GENERAL CHARACTERISTICS – Stratovolcanoes are really a smorgasbord of different types of eruptions that combined, lead to the formation (and sometimes subsequent destruction) of a steep-sided “classic” volcano such as Mt Rainier (or Mt Fuji, Japan or many other subduction zone volcano). Because the magma generated in a subduction zone has traveled through many ten’s of kilometers of lithosphere (either oceanic or continental depending on the specific subduction zone) it has become enriched in silica and is thus moderately to extremely viscous. The water from the subducting plate that led to the melt formation in the first place provides the potential for significant amounts of volatiles. The volume of a given eruption can vary from moderate to large. The name “stratovolcano” comes from in internal structure of the mountain which has stratifications or layers of different material from different eruptions. Some layers are more mafic and some more felsic. Another term that you may hear for this type of volcano is “composite.” & Mt Rainier and Seattle, WA

Stratovolcano – multiple types of eruption processes Ash cloud Stratovolcano – multiple types of eruption processes Pyroclastic flows USGS Mt Mayon, Philippines, 2006 A variety Mt St Helens eruption in 1980 also produced both an ash cloud and pyroclastic flows but the captured images for the pyroclastic flows, in particular, are not so clear as this one. Lava dome http://www.tulane.edu/~sanelson/geol111/igneous.htm USGS Mt. St. Helens, 1984

Stratovolcano - Mt St Helens USGS Before 1980 eruption built up A common scenario for stratovolcanoes is that they gradually build themselves up through only moderately explosive eruptions of lava and ash and then a much more explosive eruption partially or completely destroys the mountain. The cycle can continue multiple times. Mt St Helens is a great modern example of this. USGS After 1980 eruption blown to bits

Stratovolcano - HAZARDS Pretty much all types of volcanic hazards DEFINITELY HAZARDOUS!! HAZARDS – Nearly all types of volcanic hazards can arise in connection to a stratovolcano – lava flows, ash falls, pyroclastic flows, lahars, gasses, volcanic landslides, etc. USGS

Stratovolcanoes – PACIFIC NW Most Cascade volcanoes are stratovolcanoes (typical for subduction zones) PACIFIC NORTHWEST – The majority of subduction zone volcanoes are stratovolcanoes and the Cascades are no exception to this. Most the volcanoes in this range are (or were) stratovolcanoes including such classics as Mt Rainier, Mt St Helens, and Mt Adams. Crater Lake is shown in dashed lines because it used to be a stratovolcano until it blew itself to bits (see next section – Calderas). Stratovolcano

shield vs composite Because stratovolcanoes (=composite volcanoes) are steeper, they tend to be more visually prominent than shield volcanoes. Humans tend to perceive them as bigger. However, shield volcanoes are much much larger volumetrically – especially the ones on oceanic crust. Mauna Loa’s full height = 19,000 ft + 13,000 ft = 32,000 ft below sea level above sea level Mt Rainer = 14,400 ft

Caldera formation High viscosity Many volatiles (very explosive) Coke w/ dry ice High viscosity Many volatiles (very explosive) Large volume GENERAL CHARACTERISTICS – Calderas* form when a very silica-rich magma leads to an extremely explosive (topography obliterating) eruption. They are large relatively low relief circular(ish) depressions that can be up to 100 km in diameter. They can occur in a variety of volcanic continental settings ranging from the destruction of a stratovolcano (pictured here) to hotspots. The resulting roughly circular depression ranges from several kilometers to several tens of kilometers in diameter (~2-35 km). FLOUR BOX VOLCANO CLASSROOM ACTIVITIES ON CALDERA FORMATION: Flour Box Volcano Lesson Plan can be found at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/FlourBoxVolcano_LessonPlan_VVP.pdf Background document on monitoring deformation, seismicity, and volcanic gas is at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/VolcanoMonitoring_Background.pdf *The term caldera is used here to describe only those features formed in explosive eruptions. There is another type of circular feature that can form NON-explosively which is typically called a “subsidence caldera”. These form more gradually and non-explosively as a magma chamber below a shield volcano is emptied by lava flow eruptions. Kilauea has such a feature (it is most active shield volcano on Earth). Magma chamber partially emptied during eruption Center collapses down and forces out more magma Caldera is formed http://pubs.usgs.gov/fs/2002/fs092-02/

Caldera formation - HAZARDS Ash falls Pyroclastic flows Volcanic landslides Volcanic gasses !!EXTREMELY HAZARDOUS!! (but infrequent) HAZARDS – Caldera-forming eruptions are the most hazardous and far-reaching volcanic eruptions. Ash clouds from them can travel the globe, reflecting incoming sunlight, and causing sudden cooling for a year or more. Significant ash falls can extend for >1000 km – potentially impacting crops and infrastructure. The area around the caldera will be flattened and nearly all life extinguished. On the Coke-index you could consider this to be Coke with dry ice added so that the bottle exactly actually explodes instead of just bubbling over. http://pubs.usgs.gov/fs/2002/fs092-02/

Crater Lake Caldera, OR PACIFIC NORTHWEST Crater Lake (Oregon) was a stratovolcano until a little less than 7000 years ago when the mountain was annihilated in an volcanic eruption that blew the mountain to bits and left behind a circular depression that was subsequently filled by water.

Continental Hotspot Caldera Yellowstone, WY Just west of the Pacific NW is a great example of calderas formed when hotspot magma melts continental crust causing the formation of a very silica-rich (rhyolitic) magma – the Yellowstone calderas. The next time Yellowstone blows (and it will) it will significantly impact global society (if we are still around to be impacted). WILL IT BLOW CLASSROOM ACTIVITY developed by UNAVCO gives students a chance to review and assess for themselves the recent data related to Yellowstone magmatic activity. URL http://cws.unavco.org:8080/cws/modules/yellowstone/ http://pubs.usgs.gov/fs/fs100-03/

Yellowstone Eruptions Caldera-forming eruptions involve hundreds to thousands of times the amount of material as comes from a typical stratovolcano eruption. This image helps put the size of Mt St Helen’s 1980 eruption with the last three eruptions from the Yellowstone complex. The small area shown in dark yellow on the map is the area that received ≥1 cm ash. Compare that to the huge area of the USA covered by that depth. Close to the eruption the depth can be many meters. http://pubs.usgs.gov/fs/2005/3024/ http://www.nps.gov/yell/naturescience/eruptions.htm

Snake River Plain, Idaho Possible Hot Spot Trail from SW to NE over last 16 Ma OR 0.6 Ma 1.3 Ma 2 Ma 5 Ma 10 Ma 16 Ma ID UT NV WY 80 km Image after Smith & Siegel (2000), Windows into the Earth: the Geological Story of Yellowstone and Grand Teton National Parks

Proposed relationship between flood basalts & hotspots Columbia Flood Basalts Yellowstone hotspot track ~16 Ma When I give this lecture, I usually go over this quickly just because I find it fascinating but it is a little off topic and there isn’t enough time to go into in depth. However it is good broader-knowledge for teachers to have in their heads. A hypothesis that has been developed in the last couple decades (but over which there is still some argument) suggests that there is a relationship between flood basalts and hotspots. The idea is that a when a hot spot plume rises from the core-mantle boundary, it has a large plume head that reaches the crust first and breaks through as flood basalts. The large volume prevents significant chemical change from interactions with the continental crust. Subsequent magma of the hot spot “tail” has a much less volume but continues to erupt for many millions of years. The hotspot track appears to “move away” from the original location as the tectonic plate it is on moves. For instance the North American plate’s gradual movement towards the west-southwest has led to the series of calderas that young to the east.

Cascade Volcanoes Show real roll-over Some great visualizations with basic information about the Cascade volcanoes can be found on the IRIS Education and Public Outreach web page on Interactive Animations. Look for “Volcanoes Rollover” under “Pacific Northwest” at: http://www.iris.edu/hq/programs/education_and_outreach/animations/interactive#W Show real roll-over

Below Cascade volcanoes OPTIONAL – it is always good to keep in mind that several kilometers below the Cascade volcanoes, significant amounts of magma are cooling intrusively and forming rock bodies such as granite. The magma “plumbing systems” that feed the intrusive rock bodies are linked In complicated, not-completely understood ways with the conduit systems that feed the volcanoes themselves. ANIMATION of Cascadia Subduction Zone can be found at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/Animations/SubductionPacificNorthwest.mov GELATIN MODEL OF MAGMA INTRUSION CLASSROOM ACTIVITY does a great job illustrating the variety of different intrusive structures that can lie below a volcano. This activity can be found at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/GelatinModelOfMagmaIntrusion__LessonPlan_TOTLE.pdf VIDEO OF GELATIN MODEL OF MAGMA INTRUSION: Roger Groom, Mt Tabor Middle School, demonstrates how to set up the Gelatin Model of Magma Intrusion. This video can be found at http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/Videos/GelatinVolcano_GroomDEMO.mov

Major rock types CLASSIFICATION OF INTRUSIVE ROCKS Gabbro Diorite Granodiorite Granite OPTIONAL – In case questions arise about what the various rock types look like, were are some pictures of end member rock types.

Volcanic Hazards Pyroclastic flow (a.k.a. ash flow) Lahar (a.k.a. mud flow or debris flow) Gases Ash falls Volcanic Landslides Lava Flows Tsunamis A variety of volcanic hazards exist but I show videos highlighting a few of the most significant ones. CO2 AND CANDLES CLASSROOM ACTIVITY: This activity highlights the potential of CO2 (a non-toxic gas) to cause deaths from suffocation. The activity can be downloaded at: http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/LessonPlans/CO2Gas_Candle_Lesson_VVP.pdf CO2 AND CANDLES VIDEO DEMONSTRATION: Jenda Johnson shows how to set up and demonstrate the CO2 and candles classroom activity. The video can be found at: http://multimedia2.up.edu/Physics/TOLE/CascadeVolcanoes/Videos/PoisonGas_Demo.mov USGS

Show Understanding Volcanic Hazards clips For teachers who participated in the TOTLE 2010 workshop, you received this video with the workshop materials. Additional copies can be purchased through International Association of Volcanology and Chemistry of the Earth’s Interior (http://www.iavcei.org/IAVCEI_publications/videos_IAVCEI.htm) or Volcano Video Productions (http://www.volcanovideo.com/p1IAVCEI.html).

Mt Rainier Lahar Hazard The greatest volcanic hazard to human life in the Pacific Northwest is lahars from Mt Rainier. Research has shown that all the river valleys from Mt Rainier rivers are filled with lahar deposits that reach as far as the Ports of Seattle and Tacoma. Current estimated lahar danger is shown in this image with the communities of Orting and Puyallup having the largest at-risk populations.

Ash fall hazard USGS The volcanic hazard that will affect the widest area and number of people. Although ash falls usually do not claim humans lives immediately, they can cause significant disruption to transportation, crops, and other infrastructure activities. These effects were graphically demonstrated with the 2010 eruption of the Icelandic volcano that disrupted European (and hence global) air traffic for more than a week. Ash fall from the 1980 eruption of Mt St Helens deposited debilitating amounts of ash across central Washington and detectible amounts across more than 10 western states.

The Science of Prediction Monitoring Volcanic Activity The following slides are modified from a PowerPoint lecture produced by UNAVCO for the Will it Blow activity. WILL IT BLOW CLASSROOM ACTIVITY developed by UNAVCO gives students a chance to review and assess for themselves the recent data related to Yellowstone magmatic activity. URL http://cws.unavco.org:8080/cws/modules/yellowstone/ UNAVCO is a non-profit membership-governed consortium which facilitates geoscience research and education using geodesy (http://www.unavco.org/). UNAVCO is partnered with TOTLE and EarthScope.

Signs of Volcanic Activity Scientists look for five signs that volcanic processes are at work Eruption History Volcanic Gases Heat and Hydrothermal Activity Earthquakes Ground deformation

Monitoring Scientists use many tools to monitor volcanoes Since erupting volcanoes are dangerous, they prefer tools that can be set up and left Image from USGS (2002) Volcano Hazards Program: Strategy for reducing volcanic risk http://volcanoes.usgs.gov/

Volcanic Gases Volcanic gases are hazardous and hard to sample – they can be detected using : Spectrometers mounted on ground or airplane Samples collected by hand and analyzing in a laboratory A scientist collects gas samples (Note the protective equipment) Image from USGS Volcano Hazards Program “Measuring volcanic gases: emission rates of sulfur dioxide and carbon dioxide in volcanic plumes.” http://volcanoes.usgs.gov/About/What/Monitor/Gas/plumes.html

Volcanic Gases Trees and animals can be effected by gasses and aid detection Trees at Mammoth Mt, CA died when CO2 suffocated their roots Image from USGS Fact Sheet 172-96 “Invisible CO2 Gas Killing Trees at Mammoth Mountain, California” http://pubs.usgs.gov/fs/fs172-96/

Heat & Hydrothermal Activity Hydrothermal activity demonstrates presence of magma, not necessarily magma movement Thermal features can be monitored by: Night aerial observations Thermal (infrared) imaging Direct temperature measurements Infrared image of Mt. St. Helens’ new lava dome June 26th 2007 Image from (2007) USGS Mount St. Helens, Washington Forward Looking Infrared Images http://vulcan.wr.usgs.gov/Imgs/Jpg/MSH/MSH07/MSH07_area_new_growth_on_dome_06-26-07_FLIR_med.jpg

Earthquakes Moving magma and volcanic fluids cause quakes Most volcanic earthquakes are: <3 Magnitude Shallower than 10 km Occur in swarms Image from USGS Volcano Hazards Program “Monitoring Volcano Seismicity.” http://volcanoes.usgs.gov/activity/methods/seismic/index.php Magma and gases exert pressure Rocks break, triggering earthquakes Magma rises

Earthquakes Scientists can tell where Mt. St. Helens’ magma source is by looking at earthquake pattern.

Ground Deformation Volcanoes change shape before, during, and after eruptions Deformation is caused by trapped and pressurized gases or fluids (monitor gas emissions too!) Usually accompanied by swarms of shallow earthquakes (monitor seismicity too!) Image from USGS Volcano Hazards Program “Monitoring Volcano Seismicity.” http://volcanoes.usgs.gov/activity/methods/seismic/index.php

Ground Deformation Deformation is measured using: Tiltmeter at Mt St Helens’ crater floor Deformation is measured using: Tiltmeters (big, underground carpenter’s level) Global Positioning System (satellites triangulate position) Leveling Survey (periodic repeat measurements) Mt St Helens image from USGS Volcano Hazards Program “Monitoring Volcano Ground Deformation.” http://volcanoes.usgs.gov/activity/methods/deformation/tilt/msh.php GPS site Augustine Volcano, Alaska

Science of Prediction Table 1. SUMMARY OF VOLCANIC- ALERT LEVELS NORMAL Typical background activity of a volcano in a non- eruptive state After a change from a higher level: Volcanic activity considered to have ceased, and volcano reverted to its normal, non- eruptive state. ADVISORY Elevated unrest above known background activity After a change from a higher level: Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase. WATCH Heightened/escalating unrest with increased potential for eruptive activity (timeframe variable) OR a minor eruption underway that poses limited hazards WARNING Highly hazardous eruption underway or imminent Even though scientists could not predict the exact moment when Mt. St. Helens would erupt, they were able to save many lives by predicting that it would erupt. Table from USGS Volcano Hazards Program “USGS Volcanic Activity Alert – Notification System” http://volcanoes.usgs.gov/activity/alertsystem/

Volcanic monitoring animations by These volcanic activity monitoring animations were produced by IRIS in conjunction with Mt St Helens Institute and EarthScope. These animations can also be download from the IRIS Education and Public Outreach web page. Look for the animations under Seismic Signatures and Volcano Monitoring. URL http://www.iris.edu/hq/programs/education_and_outreach/animations#CC http://www.iris.edu/hq/programs/education_and_outreach/animations#CC

Mt St Helens erupted a lava dome 2004-2008 http://vulcan.wr.usgs.gov/Volcanoes/MSH/Eruption04/Monitoring/February2008/ Here is one final inquiry to test people with. The GPS stations generally show OUTWARD movement PRIOR to an eruption as the reservoir within the volcano swells from magma/gas additions. The GPS stations generally show INWARD movement DURING an eruption as the reservoir within the volcano deflates as magma moves up to the surface. What direction did the GPS stations move during this eruption? Outwards? Inwards?

Mt St Helens GPS data 2004-5 Lisowski et al, UNAVCO proposal, 2008 GPS stations surrounding Mt St Helens moved towards the crater during the eruptive that started in October 2004 and extended through 2005. Lisowski et al, UNAVCO proposal, 2008