The Cascade Volcanic Arc

A hazard is a situation that poses a level of threat tolife, health, property or environment. The level of hazard posed by different volcanoes can very greatly, from a weak eruption with minimal impact that causes little damage, to a voilent and life threatening explosion. Most of the sixty-plus volcanoes that erupt each year are low risk, however a combination of factors can cause a volcano to be a serious hazard. The factors causing these variations will be explained in this essay.

Imagine being on an island when all of a sudden an ear-shattering boom reverberates around you. On August 27, 1883, 10:02 in the morning, Krakatoa erupted with immense force on a modern-day Indonesia island. Almost a century later, Mount Saint Helens, located in the state of Washington, erupted at 8:30 a.m., on May 18, 1980. Although Mount Saint Helens and Krakatoa had a lot of distance from each other, they were both composite volcanoes. Composite volcanoes produce a thick lava that causes a lot of damage.

Volcanoes are one of the most destructive, yet, most beautiful things on Earth. They can make a famous city choke in its own ashes in one day, like Pompeii. Or they can turn a once damaging mountain into a graceful and peaceful home for new life, like Mount St. Helen’s. All volcanoes are unique, and no two are the same. Some erupt differently than others, some look different than others, and all are located in different spots all over the world. I learned this while completing the project and the five volcanoes I researched are examples of my discoveries. The five volcanoes I researched were Mount Hood, Mount Mageik, Long Island, Mount Muria, and Las Pilas.

St.Helens is almost twice the elevation of vesuvius, and “Mt st helens is also almost 23,000 years older than vesuvius. St helens first eruptions of st helens occurred almost 40,000 years ago, and over time those grew into an eruptive series,” this info was according to geology.com. Finally Mount St helens is “exuptive volcanic cone built from over layered ash, pumice, lava flows and volcanic domes and other deposits.” However mount Vesuvius is “part of Campanian Volcanic Arc this is a of line of volcanoes formed over substances zone created by convergence of African and Eurasian

There are over one thousand five hundred volcanoes all around the world, and when they erupt, they spew searing hot lava that changes the surface of the earth. Earthquakes, tsunamis, and volcanoes are just three examples of the many geo-processes that are constantly shaping and changing the Earth.

After more then 40,000 years of activity, one would expect that people would no longer live in the surrounding shadow of Mt. St. Helens. But regardless, many towns and cities sit inside of a zone that would face destruction if a large eruption took place. In 1980 Mt. St. Helens erupted and caused the loss of many lives and the destruction of thousands of miles of land and property. Following the eruption, the volcano has stayed extremely active. In 2004 it erupted again, building a new lava dome and sending ash and steam into the atmosphere. Since then, seismologists and volcanologists have recently discovered pockets of magma rising and that another eruption may occur soon. Even though the people of Washington know that an eruption could cause widespread devastation they continue with their lives, doing little to prepare for the potential disaster.

Albeit no emissions of magma or volcanic cinder have happened for some a large number of years, future ejections are likely. In the following few hundred years, risks will most likely be restricted to continuous fountain and hot-spring action, incidental steam blasts, and moderate to vast quakes. To better comprehend Yellowstone's well of lava and quake risks and to help ensure people in general, the U.s. Geographical Survey, the University of Utah, and Yellowstone National Park structured the Yellowstone Volcano Observatory, which persistently screens movement in the

Because of all the uncontrolled eruptions that had happened in the past, a daily satellite and real time data from instruments around the volcano give scientists loads of information about the volcano.

Mount St. Helens erupted in Washington, U.S. in 1980. This volcanic eruption was the most destructive volcanoe recorded in the United States (Watson, 1997). The explosive eruption destroyed over 250 square miles of wilderness in the surrounding area (Tarshis, 2016). No trees remained within a six mile area surrounding the volcanoe (Watson, 1997). Just outside of the six miles all trees were blown over and trees on the outer limit were seared (USGS, 2015). Four million board feet of usable timber were destroyed during the catastrophe. As a result of the eruption, 951 million dollars in disaster relief was sent to Washington from the United States government. Also, 200 buildings, 185 miles of highway and 15 miles of railway were destroyed and unusable after the volcanic eruption. The Mount St. Helens eruption also released 900,000 tons of volcanic ash onto the

that the volcano must be classified as dormant rather than extinct. Moreover, the unexpected 1995 eruption of the Soufriere Hills volcano on Montserrat, situated in the same volcanic arc, demonstrates that continuous awareness of the associated hazards is required.

Volcanoes are one of the most intimidating natural processes that occur on this planet. Usually they are associated with danger and chaos. Volcanoes are characterized by both their composition and eruption types. In this paper we will be exploring the similarities and differences between three infamous volcanoes, Mt. St. Helens, Mt. Kileaue, and the currently relevant Mt. Agung.

On the morning of May 18, 1980, the United States of America experienced its deadliest and most destructive volcanic eruption in history. Briefly succeeding a magnitude 5.1 earthquake, an enormous slab of Mount St. Helens northern flank collapsed in a massive debris avalanche. This landslide was the largest to transpire on Earth in recorded history and caused the volcanoes magma system to depressurize. With the cap of the mountain removed, superheated gases and rock fragments blasted through the side of the mountain (USDA, 2005). The lateral blast accelerated at speeds of 480 km per hour and reached temperatures of 350 °C, creating an immense area of leveled and scorched forestry. Surges of water from melting snow and glaciers capping

There are many ways to predict volcanic eruptions. Some instruments used are the seismograph, tiltmeters, and satellites. Before all these tools there was no effective way to predict volcanic eruptions. They had to rely on signs like ash coming from the volcano or earthquakes. Sometimes people did not even know there was a volcano! The first instrument invented was the seismograph in about 132 C.E. It was shaped like a cylinder with eight dragon heads around it. The text states “When an earthquake occurred, balls were released from a dragon’s mouth, probably by an internal pendulum that moved back and forth according to the direction of vibration, and were caught by a frog’s mouth, which produced noise.” (https://www.britannica.com Seismograph, by The Editors of Encyclopædia Britannica, last edited on 3-15-2017, 6 April, 2017) Another more recent instrument is called the tiltmeter, which has been used since the 1960s. It measures slight inclinations in the Earths surface. That can tell you of a volcano is in danger of erupting. (https://www.reference.com, “what is a tiltmeter” 6 April, 2017) The most recent way to predict the blasts use salatites. They monitor volcanoes from space they can detect heat, sulfur dioxide, and changes in the earths surface. They cant tell for sure when an explosion will ocurr but they can give good clues about it. (http://sciencing.com/ “Instruments Used to Monitor Volcanoes By Daniel Wilson,

Helens was a huge eruption that happened May 18th, 1980. 57 people died from the smoke. By April it was growing 5ft per day. The mushroom clouds of ash and gases more than 12 miles into the air.” states livescince. “The shock wave went 19 miles” state's fs.usda.gov. Such pulse indicated magma was on the move. On May 18, there were hundreds of earthquakes that day. The eruption lasted 9 hours. The Mount St. Helens erupted at 8:32 A.M. It went as high as 1,300 feet (396 meters). Biggest eruption over 100 years. “The first eruption of steam from the summit sent a column of ash, snow and, steam 6,000 sent into the air”, livescince.gov There were a lot of things going on that day and

Volcanoes are classified with the Volcanic Explosively Index (VEI) scale. Mount St. Helens was ranked at a five, the highest is an eight. The volcano erupted at 8:32 AM May 18, 1980. In all fifty-seven people died, twenty-seven bodies were lost, and the surrounding town was wiped out. After the explosion there was a massive mudslide.