Layers Of Lava Causes The Volcanoes example essay topic

Lateral Blast The sudden removal of the volcano's north flank released pressure on the hydrothermal and magmatic system within the volcano, triggering a devastating lateral blast to the north. The abrupt pressure release, or "uncorking", of the volcano by the avalanche can be compared in some ways to the removal of the cap from a vigorously shaken bottle of soda pop, or to punching a hole in a boiler tank under high pressure. The northward-directed lateral blast of rock, ash, and hot gas devastated an area of about 150 square miles. The blast stripped trees from most hill slopes within six miles north of the volcano and leveled nearly all vegetation for as far as 13 miles in a 180-degree arc north of the mountain. The blast deposited blocks and smaller rock fragments and organic debris over the devastated area in layers to more than three feet in thickness.

Surrounding this zone of toppled vegetation is a narrow band of scorched but standing timber in which sandy deposits are as thick as four inches; this zone has an area of about 25 square miles. The Eruption A magnitude 5.1 earthquake on May 18 (8: 32 a.m. PDT) shook loose the steepened bulge on the volcano's north flank, resulting in the largest known landslide in historic time, 2.3 cubic km (0.56 cubic miles). The entire north flank was described by an aerial observa l as "rippling" and "churning" moments before "the north side of the summit began sliding north along a deep-seated slide plane".

As the avalanche reached the north base of the cone, the topography it encountered caused it to be divided into three sections: 1. Part of the avalanche slid into Spirit Lake, raising the lake bed roughly 180 feet, and damming its natural outlet. Water displaced by the avalanche surged up the surround in hill slopes, washing the blown-down timber from the lateral blast into the lake. 2. Part of the avalanche "ramped" up and over a 1,200 foot high ridge five miles north of the volcano (Johnston Ridge) depositing debris on top of the ridge and in the South Col water Creek drainage.

3. The bulk of the avalanche was deflected westward down the North Fork of the Tout le River valley. The front of the avalanche traveled a distance of 15 miles in about 10 minutes. The resulting deposit covers the valley floor to an average depth of 150 feet, but it is more than 500 feet deep in a few places (such as 1.5 miles west of Harry Truman's Lodge). The hummocky avalanche deposit covers a total area of about 24 square miles. It consists of intermixed volcanic debris of various sizes, including blocks, pebbles, sand and silt, and blocks of glacial ice.

Mount Saint Helens: The Great Eruption Anonymous Teacher / Mentor: Rene Dol bec Mount Saint Helens is located in Southern Washington. Before May 18, 1980 the mountain stood still and was silent and beautiful. Mt. St. Helens is a composite cone, also called strato volcanoes which are very large. These types of volcanoes consists of layers of both lava and cinder.

The layers of lava causes the volcanoes to be more resistant to erosion. Andesite lava is more "sticky" than basalt and tends to be more explosive. The first recorded eruption of the mountain was estimated around 40,000 years ago. In 1802 A.D. there was a great eruption of ash.

About this time mudflows and lava flows occurred. On May 18, 1980 around 8: 31 a.m. Mount Saint Helens erupted. Denver Nelson predicted that the eruption would occur at 8: 30 Sunday morning, and missed his prediction by one minute. Seventeen missing people were presumably said to be dead from being's o close to the mountain. Including one eighty year old man who refused to leave his home, which he had lived in for fifty years, on the side of Mt.

St. Helens. Thinking that he knew the mountain so well that it would never hurt him. But he was wrong. His memorial would be one everyone at that time would remember. On July 22 two months after the eruption, the mountain sends plume high into the sky. After the big eruption, the northern side of Mt.

St. Helens was said to look like the surface of the moon. It was gray and lifeless. When the warm weather started to come, you could start to see touches of green among the grays and brown. Some small animals such as chipmunks, white-footed deer mice, and red squirrels had survived under the snow pack or below the ground. Hundred years from now, a new forest will be g rowing on the north slope of Mount Saint Helens. Everything that lived on the mountain before May 18, 1980, will be able to live there again.

It depends on what and where you are talking about. For example, there are many places on Mt. St. Helens that today still look as bleak as the days after the big eruption. These tend to be the locations closer to the volcano. On the other hand there are areas that were covered by quite thick blankets of ash and debris where the plants have come back to the point that you could be plunked down in the middle of the forest and not know that something dramatic had even happened. In general, the areas on the edges of the devastated zones are coming back the fastest because there are sources of seeds and animals in the adjacent un-devastated zones.

The hunting and fishing industry in and around Spirit Lake has not recovered at all. Volcanologist's are getting much better at predicting eruptions. Several methods are used to monitor volcanoes. These methods are applied to volcanoes that have shown signs of unrest. The past behavior of the volcano would provide the best estimate of the potential volume of future eruptions.

Volcanoes erupt because of pressure caused by gas dissolved in the magma. Different size eruptions are caused by the volume of the magma, magma supply rate, eruption frequency, composition of magma, size of the conduit, and gas content. Mount St. Helens was explosive because the magma was viscous (sticky) and the gas could not escape until it was in the throat of the volcano. Then the gas expanded and blew the lava into ash-sized fragments. Sorry, I have not seen "joe vs. the volcano" but I hear it is funny. Most movies (and some TV shows) dont worry much about the accuracy of the science information - they just want it to be exciting.