Like the other volcanoes found in the Cascade Range, Mt St Helens (MSH) had been dormant for many years. In March 1980 there were signs of an impending eruption, as several earthquakes occurred. However on the 18th March 1980, an earthquake measuring 5.1 on the Richter Scale rocked the volcano. Within a few seconds of the earthquake, the volcano erupted and the whole northern side of the volcano collapsed causing the largest known landslide in US history. This pulverised rock, glacier ice and ash wiped out all living
Before the eruption of May, 1980, the elevation at the top of Mount St. Helens was about 3 km. Mount St. Helens is a composite volcano (or stratovolcano), a term for steep sided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris. Composite volcanoes tend to erupt explosively and pose considerable danger to nearby life and property. Mount St. Helens last eruption was from October 2004 to
The tremendous eruption of Mount Tambora in April 1815 was the most powerful volcanic eruption of the 19th century. The eruption and the tsunamis it triggered killed tens of thousands of people. And the magnitude of the explosion is difficult to fathom. It has been estimated that Mount Tambora stood approximately 12,000 feet tall before the 1815 eruption, and the top 4,000 feet of the mountain was completely obliterated. Adding to the disaster's massive scale, the huge amount of dust blasted into the upper atmosphere by the Tambora eruption contributed to a bizarre and highly destructive weather event the following year.
It is this strain that led to the Sichuan quake. The 2008 Sichuan earthquake occurred where the eastern part of Tibet, forced further eastward, overrides the Sichuan basin at a rate of about 4 mm/year. The rupture of the fault started in the mountains northwest of the city of Chengdu and then, over the next 50 seconds, traveled at least 200 km toward the northeast, tearing apart the land along the front of the mountain range. That at the epicenter, the depth of the rupture was only about 10 km below the surface. The amount of shaking correlates with rupture depth.
This type of devastation happened on March 11 2011 in Japan when a very powerful tsunami ruined the land, and on October 17 1989 when California was hit by huge earthquake named Loma Prieta. This essay will compare and contrast these two world shaking events and give some research about the two events as well. Maybe you will learn about some interesting facts about the two. A earthquake is described as a sudden and violent shaking of the ground, resulting from the movement within the earth’s crust or from volcanic action. It sometimes causes great destruction.
St. Helens is a very closely monitored volcano due to its previous eruptions. It is one the most seismically active volcanoes in the Washington and Oregon Cascades. Since establishing a full seismic monitoring network in 1980 the millions of
It is a roughly triangular-shaped area about 250 miles on a side. On its fringes the elevation of the plateau is about 4,000 feet above sea level, and at its lowest point it is about 400 feet. The journals of Lewis and Clark briefly note the Plateau. The Columbia plateau formed between 6 million and 16 million years ago as the result of successive flows of basalt. The Columbia Plateau province is enclosed by one of the world’s largest accumulations of lava.
The oldest ash deposits were erupted at least 40,000 years ago onto an eroded surface that's still older volcanic and sedimentary rocks. Intermittent volcanism continued after the glaciers disappeared, and nine main pulses of pre-1980 volcanic activity have been recognized. Two months before the big explosion there was a 4.1 magnitude earthquake that hit underneath Mount Saint Helens, then seven days after that a 250 foot hole was in the mountain and released a plume of ash. The entire area was evacuated. Then on May 18, 1980 it happened, 57 people were killed, over 7,000 animals were killed as well.
The 2010 Chile earthquake is ranked as the sixth largest earthquake to ever be recorded by a seismograph. It had a magnitude of 8.8, lasted three minutes and could be felt over 1,491 miles away. It hit on Saturday, February 27, 2010 at 03:34 a.m. local time (06:34:14 UTC). The epicenter was located 200 miles southwest of the Chilean capital of Santiago with latitude of -36.122 and longitude of -72.898. The earthquake was 22 miles below the surface of the Pacific Ocean from a 300 to 375 mile stretch of the fault that separates the Nazca and South American tectonic plates.
9, 000 of those being foreigners. The Tsunami’s energy was so great the wave traveled around the world three times. Seven years later in 2011 an earthquake 60km off the east coast of Tohoku with a magnitude of 9.0 on the Richter scale struck Japan. The earthquake triggered a huge Tsunami which reached heights of 133 ft. and killed around 15, 839 people, injured 5950 and left 3642 unaccounted for. Causes When a dense oceanic plate collides with a less dense continental plate the denser oceanic plate subducts under the less dense continental plate.