They can cause widespread destruction, such as the 1980 eruption of Mt St Helens. Lahars are a secondary effect of a volcanic eruption and are cement-like mudflows consisting of volcanic ash and water. They often occur in the days following an eruption when people are at their most vulnerable and with the capacity to travel up
a. strain buildup only b. location of foci c. magnitude of P-waves [pic] d. reoccurrence rates of earthquakes in an area and the rate of strain buildup 2. What are most earthquakes associated with? a. rift valleys b. mid-ocean ridges c. divergent plate boundaries [pic] d. plate boundaries 3. At what point in the graph would a rock be permanently deformed? [pic] a. at the start of the stress [pic] b. past
Less rainfall means there is less water to enter into the facility and transport radioactive waste. On the negative side there are three things which cause me an unsteady feeling. First, the mountain is in an area where there has been volcanic activity. Because of the activity strong gases have entered into the ground which could cause explosions to be destructive. Secondly, the area has several faults running through the area where the proposed facility was to be built.
Scientists have since seen these patterns as precursory to eruptions at many other volcanoes, including the 2004-2008 eruption of Mount St. Helens. At Mount St. Helens the value of an extensive system of seismic sensors has greatly improved our ability to determine the location and depth of earthquakes, and our ability to understand the physics of magma systems underground. The lack of short-term seismic or other geophysical indications in the hours and days prior to the May 18, 1980, debris avalanche, as well as prior to many short discrete explosions both before and after May 18, underscores that fact that scientists and public officials will not always have warning sufficient to issue short-term predictions of impending eruptive activity. Today, seismic
In which ways does volcanic activity vary in relation to the type of plate margin along which it occurs? (10 Marks) Volcanic activity can occur at constructive or destructive plate margins, but it can also occur at hotspots in which no plate margin is involved. At destructive margins two plates which are moving together can be either both oceanic plates or one continental and the other oceanic. In the case of one continental plate and one oceanic plate, volcanic eruptions are very violent and emit andesitic or rhyolitic lava. These types of lava are very viscous due to its high silica content.
Discuss the view that the impact of the earthquake hazards depends primarily on human factors? An earthquake, a sudden violent shaking of the ground can be caused by a number of things from seismic activity and resulting in varying impacts. The cause of an earthquake are a result of built up pressure under the earth’s crust, the pressure comes from the movement of the tectonic plates, they can occur on any plate boundaries. Although the majority of the earthquake hazards come from the physical factors, human factors can determine the severity of the event. The impacts created from an earthquake can come from the physical factors of the size, the location of the epicentre and the surrounding areas such as a ground type and the lithology of the rocks.
This tells us that it’s a powerful earthquake, reaching and being felt by farther away places. This earthquake makes itself more dangerous with little or no warning. Earthquakes are probably the most dangersome natural occurring disaster encountered. South Carolina is located within the interior of the North American plate, far from any plate boundary. An earthquake is what happens when two blocks of earth suddenly slip past one another.
Gases dissolved in magma provide the motive force of volcanic eruptions, sulphurous volcanic gas and visible steam are usually the first things noticed on an active volcano as well as others that escape unseen for example through hot fumaroles, active vents, and porous ground surfaces. The limitations of taking these samples are remote location of these sites, intense and often hazardous fumes, frequent bad weather, and the potential for sudden eruptions can make regular sampling sometimes impossible and dangerous. Measuring gases remotely is possible but requires ideal weather and the availability of suitable aircraft or a network of roads around a
What do earthquake swarms indicate? (page 94, para 2 to page 95) Earthquake swarms indicate that new fractures were forming. Swarms can be used as an early indication that magma from a storage zone is being injected into the rifts were these new fractures are happening. 3. What is "summit deflation"?
This eruption was an explosive eruption. 8. At first, the surrounding area experienced many small earthquakes, which suggested possible magma movement. The magnitudes of the earthquakes increasingly got higher as the volcano got closer to erupting. Then, explosions of ash, rock, and ice became common everyday occurrences.