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  The eruption of a volcano can have devastating effects on surrounding landscapes and cultures. More than 300,000 people have died from volcanic activity in the past 500 years, and volcanoes have also caused huge amounts of damage to structures and agricultural development. Figure V-14 shows a house being set on fire by advancing lava from Kilauea volcano in January, 1960.   The United States Geological Survey web site provides a table that summarizes notable volcanic activity that resulted in at least 300 fatalities since the year 1500.   What can be done to mitigate the destructive power of volcanoes?     Monitoring and Prediction While we cannot control a volcano's ability to erupt, vigilant monitoring of active volcanoes can allow scientists to predict when eruptions may occur. When accurate predictions are made, people can be evacuated from potential eruption zones, and both lives and property can be saved.   Scientists use a variety of methods to monitor volcanic activity, including:   a. Measurement of Gases. Volcanoes constantly emit gases through vents on the surface. Changes in the quantities of these gases - particularly carbon dioxide and sulfur dioxide - may indicate that the volcano is preparing to erupt. Therefore, scientists carefully monitor gas levels at active volcanoes. Gas is collected at vents and fumaroles, then taken back to a lab for analysis. Gas collection is a tricky business, though, since it requires scientists to travel to hazardous areas on the volcano's surface. Some remote techniques for gas collection are now being used as well.   b. Measurement of Ground Deformation. When magma rises through a conduit inside a volcano, it exerts an immense upward pressure on the sides of the volcano, which causes the volcano to change shape, or deform. Therefore, tracking ground deformation is an important way to monitor volcanic activity. Scientists track ground deformation by placing a variety of sensitive instruments, including tiltmeters (which measure the angle of a volcano's slope) and GPS receivers, in appropriate locations on the surface of the volcano. Fig. V-15 shows a GPS receiver that was placed on Augustine Volcano, near Anchorage, Alaska, to detect deformation on the volcano's surface.  
    c. Seismicity. Pressure from rising magma also causes earthquakes to occur inside a volcano before an eruption. Therefore, an increase in seismic activity may be another indicator that a volcano is about to erupt. Scientists place a network of seismic monitoring instruments on a volcano's surface in order to keep track of changes in seismic activities.   Other techniques, such as remote sensing and hydrologic monitoring, are also used to predict volcanic risk at sites throughout the world. Such monitoring truly does save lives. In 1980, scientists monitoring Mount St. Helens in Washington State noticed a marked increased in seismic activity and ground deformation. Their warnings allowed for the evacuation of people from the eruption zone and probably saved thousands of lives.   For more information on the scientific monitoring of volcanoes, click here.     Personal Preparedness The Federal Emergency Management Agency (FEMA) recommends the following steps for staying safe before, during, and after a volcano eruption:   BEFORE Learn about your community warning systems.   Be prepared for these disasters that can be spawned by volcanoes: Earthquakes, Flash floods, Landslides and mudflows, Thunderstorms, and Tsunamis.   Make evacuation plans.   Plan a route, and a backup route, that will allow you to reach high ground, away from the eruption.   Develop an emergency communication plan.   In case family members are separated from one another during a volcanic eruption (a real possibility during the day when adults are at work and children are at school), have a plan for getting back together.   Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone knows the name, address, and phone number of the contact person.   Have disaster supplies on hand: Flashlight and extra batteries Portable, battery-operated radio and extra batteries First aid kit and manual Emergency food and water Non-electric can opener Essential medicines Cash and credit cards Sturdy shoes   Get a pair of goggles and a throw-away breathing mask for each member of the household.   Contact your local emergency management office for more information on volcanoes.   Evacuation: Although it may seem safe to stay at home and wait out an eruption, doing so could be very dangerous. The rock debris from a volcano can break windows and set buildings on fire. Stay safe. Follow authorities' instructions, and leave the area before the disaster begins.     DURING Follow the evacuation order issued by authorities.   Avoid areas downwind of the volcano.   If caught indoors, close all windows, doors, and dampers and put all machinery inside a garage or barn.   Bring animals and livestock into closed shelters.   If trapped outdoors, seek shelter indoors.   If caught in a rockfall, roll into a ball to protect head.   Avoid low-lying area where poisonous gases can collect and flash floods can be most dangerous.   If caught near a stream, beware of mudflows.   Protect yourself: Wear long sleeved shirts and pants. Use goggles to protect eyes. Use a dust-mask or hold a damp cloth over face to help breathing. Keep car or truck engines off.   Stay out of the area. A lateral blast of a volcano can travel many miles from the mountain. Trying to watch an erupting volcano is a deadly idea.   Mudflows. Mudflows are powerful "rivers" of mud that can move faster than people can walk or run. Mudflows occur when rain falls through ash-carrying clouds or when rivers are dammed during an eruption. They are most dangerous close to stream channels. When you approach a bridge, first look upstream. If a mudflow is approaching or moving beneath the bridge, do not cross the bridge. The power of the mudflow can destroy a bridge very quickly.     AFTER Listen to a battery-powered radio or television for the latest emergency information.   Stay away from volcanic ashfall.   When outside: Cover your mouth and nose. A number of victims of the Mount St. Helens volcano died from inhaling ash. Wear goggles to protect your eyes. Keep skin covered to avoid irritation or burns. If you have a respiratory ailment, avoid contact with any amount of ash. Stay indoors until local health officials advise it is safe to go outside.   Avoid driving in heavy ashfall. Driving will stir up more ash that can clog engines and stall vehicles.   Clear roofs of ashfall. Ashfall is very heavy and can cause buildings to collapse.   Remember to help your neighbors who may require special assistance—infants,
elderly people, and people with disabilities.
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