Mount St. Helens is a volcanic mountain in the Cascade Range in North America, in the state of Washington. It is, perhaps, the most famous mountain in the range, and certainly is the most active volcano in the area today. In fact, it has probably been the most active of the Cascade volcanoes for over 4000 years. On May 18th, 1980, the mountain erupted. Becoming one the largest volcanic eruptions in U.S history.
Mount St. Helens lies on a Convergent boundary plate. These are the most geologically active plate, the mountain lies mainly on the Continental crust of the Convergent boundary plate. Mount St. Helens is 8,366' or 2,550 m high. The radius of Mount St. Helens is about 6 km at the base, and the elevation of the base is about 1 km above sea level. Before the eruption of May, 1980, the elevation at the top of Mount St. Helens was about 3 km.
The Columbia Plateau province is enclosed by one of the world’s largest accumulations of lava. Over 500,000 square kilometers of the Earth's surface is covered by it. The topography here is dominated by geologically young lava flows that flooded the countryside with amazing speed, all within the last 17 million years. Over 170,000 cubic kilometers of basaltic lava, known as the Columbia River basalts, covers the western part of the area. These tremendous flows erupted between 17-6 million years ago.
The amount of shaking correlates with rupture depth. The closer the rupture is to the surface, the stronger the shaking. Motion along the southern edge of the fault was predominantly dip slip, leading to an increment of uplift of the mountain range and subsidence of the Sichuan basin. Facts: Thirty times more powerful than the earthquake that devastated Kobe, Japan in 1995, the Sichuan earthquake lasted for about 80 seconds and caused the ground surface to shift about seven meters near the epicenter of the quake. Many Chinese refer to its as the
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.
Iceland is warmed by the Gulf Stream. The Laki eruption wasn’t really a single event, but rather 8 months’ worth of lava flows and explosions that ejected an astounding 14.7 km cubed of ballistic lava that came out of 140 vents. The eruption was caused by small earthquakes that were hardly detected by the seismometers the eruption caused a gigantic amount of smog and poisonous gasses to envelope Iceland in a matter of days which caused at least 10,000-15,000 deaths in Iceland alone. Consequences in Iceland Affects of a volcanic eruption An estimated 20–25% of the population died in the famine and fluoride poisoning after the fissure eruptions ceased. Around 80% of sheep, 50% of cattle and 50% of horses died because of
A volcano is a surface landform resulting from the extrusion of magma from underground as lava, ash, rocks, and gasses are erupted in various proportions. A hazard is something that poses a threat to life, the environment or property. Volcanoes can compromise all these things through the many hazards volcanoes presents. These include lahars, flash flooding, landslides, pyroclastic flows, ash clouds and many others. Each year, around 60 major volcanoes erupt globally.
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.
NOVA: Volcanoes Volcanoes are landforms where molten rock erupts through the surface of the planet. Think of them as pimples on the face of the earth. Today, there are over 1,500 active volcanoes on earth’s surface. Volcanoes cause serious hazards to not only people, but the environment and the nature around us as well. If an eruption were to occur, a number of life-changing things would happen.
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.