Why did Harry Truman die in the Mt St. Helen’s eruption?
Mt St Helens before the eruption in 1980.
Mt St. Helens after the eruption in 1980.
Why did Harry Truman die in Mt St Helen’s 1980 eruption?
Mount St Helens is a volcanic mountain which is found on the west coast of the United States of America. The USA lies in the continent of North America. Mount Saint Helens can be found on the state of Washington and it is approximately 95 miles south of Seattle (Capital city of the State Washington) and 50 miles (80 km) northeast of Portland, Oregon. Mount Saint Helens lies in the mountain range of Cascades which is mainly made up of volcanic mountains such as Mount st Helens due to the fact that the volcano is located in the Cascade Range and the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.
Fig 1. A Map of the Cascades mountain range that shows the volcanoes and mountain ranges.
Fig 2. A Picture of the Cascades mountain range that shows some of the volcanoes located there.
Mount St Helens.
Mount St Helens is a type of strato-volcano most commonly known as a composite volcano. Composite volcanoes are volcanoes that have steep sides and are made up of alternate layers of ash and lava from previous eruption. Composite volcanoes do not erupt frequently as opposed to shield volcanoes however when they do erupt, they release Pyroclastic flow and Lahars. This is because the Composite volcanoes are mainly found on the plate margin of a destructive plate boundary. The reason why they are found at this plate boundary is because destructive plate boundary is when an Oceanic Crust and Continental Crust are pushed towards each other. Now the oceanic and the continental crusts are different types of plate boundary which have different properties. Consequently, because the oceanic crust is much denser and heavier than the continental crust, it forced to sub-duct underneath the Continental Crust. As the Oceanic crust sub ducts, it starts to melt due to the high amount of heat being generated by the friction by the two plates moving but also the heat from the mantle also causes it to melt. A sub-duction zone is formed where the oceanic crust sub-ducts under the continental crust and ocean trenches are formed as a result from the seduction. Also the melted oceanic crust now becomes molten rock/magma. The magma that has recently been formed is less dense than the old one which means that the magma that has recently been formed floats on top of the old one. Consequently, it is now under high pressure and erupts at the surface as a volcanic eruption, spewing out ash, lahars and Pyroclastic flow as it erupts. On 18th May 1980, an earthquake measuring a magnitude of 5.1 caused a landslide on the northern flank of the volcano. This resulted in the sudden release of pressure that was being held in the crypto dome and a huge eruption occurred in the form of a lateral blast. The Plinian eruption lasted for about 9 hours.
