It increased by 7 ft a day.” Earthquakes You can predict when a volcano will erupt because you get earthquakes. This is because most volcanoes follow a regular pattern of increasing seismic activity as the eruption is about to take place, usually in the form of small earthquakes. Scientist use special equipment seismometers that tell and record earthquakes that happen underneath the volcano. Long period earthquakes- are beneath volcanoes and are believed that it is caused by magma moving through cracks that then shake the ground. Short period earthquakes- earthquakes under the volcanoes that is believed to be caused by rock breaking events Both types of
Earthquakes are caused by the rift and abrupt movement of two rocks that suddenly slip past one another. Earthquakes occur along faults which are fractures in the lithosphere where sections of rock move past one another. There are three important parts to an earthquake: the focus, the epicenter, and seismic waves. The focus is the point on the fault where the separation occurs and from where the seismic waves are formed. The epicenter is located directly above the focus on the earth’s surface.
The force of one plate being dragged under another causes intense friction and the pressure increases. Eventually, there is so much pressure that the plates suddenly jolt, causing an earthquake. Where an oceanic plate meets a continental plate, sediments are thrust upwards. Due to the friction caused by the plates scraping against each other, the temperature in the mantle increases. Magma rises forming a long chain of volcanic fold mountains for example the Andes.
(Some geologists argue that this portion of the Eurasian Plate is actually a fragment of the North American Plate called the Okhotsk microplate.) A part of the subduction zone measuring approximately 190 miles (300 km) long by 95 miles (150 km) wide lurched as much as 164 feet (50 metres) to the east-southeast and thrust upward about 33 feet (10 metres). (“Japan Earthquake and Tsunami of 2011, 1”) A series of extremely destructive tsunami waves followed the 9.0 earthquake along with the dozens of foreshocks and aftershocks that came with it. The city of Sendai, its surrounding area and airport were pounded by a wave
Discuss the view that the impact of earthquake hazards depends primarily on human factors [40] An earthquake is a tremor or shockwave in the earth’s crust that is caused by the sudden movement of the crust, resulting in the earth shaking. Most earthquakes are a consequence of tectonic plate movement by tension causing a sudden release of energy or rubbing. These normally occur at plate margins or along fault lines and can cause hazards which need to be prevented where possible. Earthquakes can therefore occur at all plate boundaries, destructive, constructive and conservative but the most damaging tend to happen at destructive margins where the earthquakes have a high magnitude due to the rubbing of the oceanic and continental crusts. A hazard is a natural event that has the potential to effect both life and property.
Kobe earthquake Japan is positioned on the margin of the Eurasian plate. The Philippine Sea Plate is subducted below the Eurasian plate at a rate of about 10 centimetres per year resulting Japan having greater than average seismic and volcanic activity. The city of Kobe is located just to the north of where the Philippines Plate is subducting beneath the Eurasian plate, which fractured as a result, to produce the median tectonic line. This then puts a strain on the crust behind it which has then fractured to produce a new fault zone. Movement in this fault zone resulted in the great Hanshin earthquake.
When the pieces of lava collect on a steep slope, then the side of the delta crumbles often and creates a bunch of submarine landslides. Collapses like this can catch unsuspecting people and push them into the ocean and sometimes also cause big explosions. Lava deltas get wider to the sides as well as longer out into the water until a landslide happens or until the lava flow to the water is stopped. First, the pahoehoe lava is thick and slowly moves across the beach or drops over a small cliff. Waves from the ocean slosh onto the lava, causing the lava to cool at a rapid pace and break into tiny glass pieces.
The earthquake occurred in the backarc region of the convergent boundary where the Pacific Plate subducted beneath the Eurasian Plate. The earthquake shaking caused moderately severe damage, VIII on the Mercalli scale. The jolting movement of the seabed made the water rise and fall, which set off a terrifying tsunami. The fast-moving waves spread in all directions. They hit Okushiri less than four minutes later.
There are divergent boundaries where the plates are moving away from each other and new land is formed as magma is released from inside the mantle. There are convergent boundaries where the plates are moving toward each other. At convergent boundaries mountains or trenches can form. The last type of boundary is a transform boundary where the plates move past each other and can cause an earthquake
The plates meet with each other, and if rough spots cause the movement to stop at the edges, the motion of the plates continue. When the rough spots can no longer hold, the sudden release of the built-up motion releases, and the sudden movement under the sea floor causes a submarine earthquake. This area of slippage both horizontally and vertically is called the epicenter, and has the highest magnitude, and causes the greatest damage. As with a continental earthquake the severity of the damage is not often caused by the earthquake at the rift zone, but rather by