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
Plate Tectonics Press Release Assignment Geology/101 An earthquake is the shaking of the ground cause by an abrupt shift of rock along a fracture in the Earth, called a fault. An earthquake is caused by the breaking and shifting of rock beneath the Earth’s surface. Ground shaking from earthquakes can collapse buildings and bridges; disrupt gas, electric, and phone services; and sometimes trigger landslides, avalanches, flash floods, fires, and huge, destructive ocean waves (tsunamis) (www.fema.gov/hazard/earthquake/facts). So the question that everyone wants to know is why does the planet move when the plates move? The planet moves whenever the two plates get tangled together.
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
I will be discussing factors that cause differences in hazards posed by volcanoes. I believe the most important factor is the location of a volcano and the type of volcano. The most explosive and therefore dangerous volcanoes are found on destructive plate boundaries (Over 80% of the worlds volcanoes occur at these boundaries) for example the eruption of the Nevado del Ruiz in Colombia on the 13th November in 1985 which killed over 25000 residents of Arenas and Armero. At destructive plate margins, the oceanic crust is denser than continental crust and is therefore subducts under the continental crust. Due to high temperatures in the mantle of around 3000 degrees centigrade, this oceanic crusts melts and then rises due to the convection currents in the aesthenosphere .
An example of catastrophism is an earthquake. This is an example of catastrophism because it shows a sudden change. Uniformitarianism is the principle that states the geological processes that happened earlier in history can be explained by the geological processes that are happening gradually today. This principle is what people began to consider shaped the Earth. An example of uniformitarianism is when rock wears away and erodes.
I shall use examples of the Kobe Earthquake 1995, Boxing Day Tsunami 2004 and the Haiti Earthquake 2010. The earthquake of 2004 was caused by subduction of the Australian plate and the Eurasian Plate ,a 15-20m slip occurred along the fault line which then caused an earthquake measuring a 9.1 on the Richter scale. This a very high recording on the Richter scale so therefore it would always cause devastating hazards , but human factors could be seen as making the impacts far worse. The earthquake in the ocean had caused a tsunami to occur within the Indian Ocean. The wave reached up to 30 metres high causing devastation to the 13 countries surrounding the ocean.
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. Volcano: include the type of lava, where magma is derived, and why this setting produces hazards b. Earthquake: magnitude and amount of displacement or offset 6. Describe the type of hazards in terms of cause, hazard definition, and location (example-tsunami inundation occurred within 1 mile of coastline in low lying areas). 7. Fatalities 8. Damage: 2-3 specific examples of structural damage (earthquakes); areas covered with volcanic debris (volcanic eruption); any other types of damage 9.
Earthquakes Sheila Fangmeier GEO101 – Earth Science Colorado State University – Global Campus Karen Stelly October 5, 2014 Earthquakes “An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves” (Earthquake, 2014). Seisometers measure earthquake magnitude and intensity based on two scales, the Richter and Mercalli. An earthquake’s magnitude can range from less than 2.0 to greater than 9.0 on the Richter scale and its intensity I to greater than VIII on Mercalli (Richter magnitude scale, 2014). The depth focus is important to how much damage can occur on the Earth’s surface. An earthquake’s depth can be considered shallow (less than 70km), intermediate (between 70km and 300km), or deep (300km to 700km) (Earthquake, 2014).