GEOLOGY 170 REPORT:
MT. ST. HELENS:
Mount St. Helens is located in southwestern Washington about 50 miles northeast of Portland, Oregon.Mount St. Helen is one of several volcanic peaks that dominate the Cascade Range in the Pacific Northwest. The principal part of the range extends from Mount Garibaldi in British Columbia, Canada, to Lassen Peak in northern California. It was considered one of most beautiful mountains in the Cascade Mountain Range. St. Helens was often compared to Mount Fuji in Japan because of the mountain’s similarity in appearance. All of that would change on May 18, 1980 when the young and quiet Mt. St. Helens decided to become an active volcano and cause the worst natural disaster in the history of the U.S.
The eruption was triggered by a massive mudslide on the side of the mountain. All the material that slid away from the mountain caused a lateral blast that could be heard hundreds of miles away. The lateral blast only lasted a few minutes of a nine-hour eruption. After the mountain was forced open by the lateral blast the mountain erupted in full force. Mt. St. Helens ejected a cloud of ash 15 miles into the air. The ash being ejected into the atmosphere
As soon as the mountain erupted the National Guard was called in to try and find survivors. As soon as it was possible and clear enough to fly into the blast zone choppers were sent to see the damage that has been done. The terrain, which at one time was green, was now gray and burnt. The smell of sulfur was in the air. A total of 60 people were dead or missing after the eruption. There was a large rescue effort that saved many lives but many lives were lost instantly. Scientist knew that the eruption was probably going to come because of earthquakes on and around St. Helens. But the large mudslide sped up the process dramatically. After all was said and done to Mt. St. Helens lost roughly one cubic mile of material from its summit. The mountain lost 1,300 feet of its crown during the eruption. The once cone shaped mountain now resembled a horseshoe. The eruption made all of the newspapers in the world. In that time Mt. St. Helens was the center of the worlds attention.
Twenty years after the eruption of Mt. St. Helens the question that most people ask is whether or not this kind of catastrophe will happen again in the future. The study of volcanoes has come leaps and bounds since 1980. Trying to predict when and where an eruption may occur is much more affective now. Mt. St. Helens has roughly nine eruptions in the past 50,000 years. That’s not counting the activity in 1980. The most recent and best known of the pre-1980 eruptive periods began with a major explosive eruption in 1800 AD.For the next 57 years, intermittent relatively small explosive eruptions, lava flows, and the extrusion of lava dome followed this event. Assuming that Mount St. Helens behaves as it did in the 19th century, the present activity could continue intermittently for years, possibly decades. Such activity could include the outpouring of lava flows (not observed to date), as well as some dome growth and small explosive activity. The chance of another catastrophic landslide and blast comparable to
The eruption of May 18, 1980 is pretty low. The past history of the volcano suggests that one or more explosive eruptions with heavy ash fall comparable to that of the May 18, 1980, eruption might occur before Mount St. Helens returns to a dormant state. This history of intermittent activity is one of the most important reasons why scientists continue to monitor the volcano. They try to detect the sustained seismic activity and ground deformation that can be expected to cause any massive infusion of new magma required to break the pattern of dome building in the 1980s and to feed an explosive eruption of major proportions. Basically St. Helens isn’t looking like it is going to be as active as it has in the past but it’s not going to go into it’s dormant stage.
The eruption of Mt. St. Helens will be a day that nobody will ever forget. Everyone who was alive when it happened remembered where they were and what they were doing at the time. Scientist learned a lot from the St. Helens eruption and what effects it has on the environment surrounding it. The wilderness surrounding the volcano is starting to grow back and turn to its green natural color again. One thing that I think a lot of people learned about this eruption is they have to respect the volcano’s that we live next to. They are really nice to look at with there snow tipped peaks but in split second they can release destruction that can affect thousands a lives and wipe out thousands of acres of forest. But with scientist willing to study and predict when these eruptions will occur can save lives and make these eruptions be as simple as they can be.