Mount+St.+Helens,+Washington,+1980+(304)

Type in the content of your page here. materials produced in eruption __//Nature Of Eruption//__

St Helens is a stratovocano.Which means it is very steep and has eruptions that are very explosive.The volcano is basically a dormant one.It has not erupted until 1980s after it 123 years of slumber.The eruption was violent as it caused a lot of volcanic ashes to be blasted into the atmosphere and caused landslides. A [|volcanic ash] column rose 80,000 feet (24,400 m) into the [|atmosphere] and deposited ash in 11 U.S. states.[|[2]] At the same time, snow, ice, and several entire [|glaciers] on the volcano melted, forming a series of large [|lahars] (volcanic [|mudslides]) that reached as far as the [|Columbia River], nearly fifty miles (eighty kilometers) to the south.

//**__ Human response (before and after) __**// Before after
 * Long before settlers arrived from the east, Mt. St. Helens was a sacred place to the local Indian tribes. They had been witnesses to its long history of eruptive behavior and ancient legends caused them to give the mountain a wide berth. **

||
 * __ Human response (before) (by hari) __**
 * **One week later, on March 27th, the mountain smudged the usually pristine snow at her summit with its first puff of ash. No one on the groud knew what had happened at first because the top of the mountain was encased in clouds for her first show. The small explosion left a 250 foot wide crater in the otherwise perfect cone. On March 30th there were a record 79 earthquakes recorded on the mountain.**


 * **On April 3rd, the first harmonic tremors were recorded signaling the movement of magma somewhere deep within the dome. The crater was by now 1,500 feet wide. Explosions of ash, rock and ice chunks were almost a daily occurrence by this time. The mountain had taken on an eerie, sinister look with her ash covered slopes.** ||


 * **For safety reasons, a "Red Zone" and a "Blue Zone" were mapped out around the mountain. Swarms of tourists wanted to get as close as possible to the waking giant but because of the scientists inability to predict the time and magnitude of an eruption, they needed to keep people out of harms way. Despite the best efforts of local police, there were too many small logging roads that criss-crossed the area to keep out all of the curious onlookers.** ||


 * **In late April a noticeable "bulge" began to form on the north face of the mountain. The bulge was created by the building pressure of hot gases and magma inside the mountain. All through early May the bulge grew at an astonishing 5 feet per day. The mountain soon lost its perfect cone shape that had characterized it as the "Mt. Fugi of the West".** ||


 * **On May 17th, frustrated home owners living in the "Red Zone" threatened to break through roadblocks to get to their homes. A convoy of 35 home owners were escorted in by police to retrieve personal belongings from their homes and summer cabins. Another trip into the "Red Zone" was planned for the next morning, May 18th, at 10 a.m.** ||

Despite the devastation left behind on May 18th, not everything in the blast zone was destroyed. Areas that seemed like they would never recover have surprised scientists with the resilience of nature. Many animals and plants who were fortunate enough to be beneath the spring snowpack or underground, soon found their way through the thick ash to the surface. Several lakes that were still frozen over went virtually untouched even though all the life around them was decimated. One of the first plants to reappear, appropriately enough, was the fireweed (pictured above). The presence of plant life enticed deer and elk to return to the area. With their wanderings, they stirred up even more ash, freeing seeds and shoots of plants still buried. Even though there were over 1500 elk killed as a result of the eruption, the elk population had returned threefold by the early 1990’s thanks to mild winters, an abundance of food on the debris avalanche, and the lack of human interference. **//__No. of casualties/Main cause of casualty__//**
 * __ Human response (after) (by hari) __**

//**__ Death __**//** 57 people were killed as aresult of the eruption. Of these, 21 bodies were never recovered from the blast zone. ** //**__ Animals __**// 7,000 big game animals, 12 million Chinook and Coho salmon, and millions of birds and small mammals are believed to have died in the eruption. //**__ Damage Estimates __**// $1.1 billion for timber, civil works and agricultural losses. This does not include money for personal property losses, the cost of ash clean-up, or the loss of tourism in the area immediately after the eruption. // [Giang & Mengshan] // //  [] ? // St Helens is a stratovocano.Which means it is very steep and has eruptions that are very explosive.The volcano is basically a dormant one.It has not erupted until 1980s after it 123 years of slumber.The eruption was violent as it caused a lot of volcanic ashes to be blasted into the atmosphere and caused landslides.
 * May 18th, 1980, 8:32 am (PDT), Mt St Helens erupted. **