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.
Index Terms — Seismic Data Acquisition, Earthquake, Accelerometer, ARM, ADC I. INTRODUCTION An earthquake is a natural disaster which can cause damage and loss of lives. It is the result of a sudden release of energy in the Earth’s crust that creates seismic waves. Degree of the damage caused by an earthquake depends upon the distance between the affected area and the epicenter, and also upon the magnitude which indicates how much energy is released from the origin to the Earth’s crust [1]. Analysis of seismic signals is done by seismometers at monitoring stations.
Movement in this fault zone resulted in the great Hanshin earthquake. A 30-50 km long rupture of a strike-slip fault occurred close to and under downtown Kobe. The eruption towards the north ruptured towards Kobe. The earthquake’s shallow depth of 16 km and close proximity to the built-up area meant that buildings and structures were subjected to much ground-shaking and soil liquefaction On Tuesday, January 17th 1995, at 5.46 am (local time), an unexpected earthquake of magnitude 7.2 on the Richter scale struck the Kobe region of south-central Japan, the shallow depth of the focus which was only about 16 kilometres below the surface and the fact that the epicentre occurred close to a very heavily populated area caused a great destruction. Seismic shockwaves travelled from Awaji Island (the epicentre) along the Nojima Fault to the cities of Kobe and Osaka.
(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
Second, the process of the two natural events is different than each others. The volcano usually happens and forms near the plates boundaries of the ground. First, the crust is moving a little bit and causing melt because of decreasing the
Compare and Contrast two disaster hotspots in term of their hazards and management of their hazards A hazard hotspot can be defined as a place that has two or more natural hazards affecting it. An example of an MEDC that is a Hazard Hotspot is California, in South-Eastern USA. An example of an LEDC Hazard Hotspot is the Philippines, a group of lots of islands in South-East Asia. California is located on the San Andreas Fault, a conservative plate boundary. This means that it is very susceptible to earthquakes e.g.
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
The actual speed of P and S seismic waves depends on the density and elastic properties of the rocks and soil through which they pass. In most earthquakes, the P waves are felt first. The effect is similar to a sonic boom that bumps and rattles windows. Some seconds later, the S waves arrive with their up-and-down and side-to-side motion, shaking the ground surface vertically and horizontally. This is the wave motion that is so damaging to structures.
Mud volcanoes, sometimes called ‘sedimentary’ or ‘gas-oil’ volcanoes, are an interesting natural phenomena that occur around the world generally along points of weakness in the Earth’s crust such as fault lines. They act as pressure valves to release gases, mineral water and sometimes traces of oil along with mud also known as breccia from as deep as 10-12 km below the earth’s surface. The size of mud volcanoes very dramatically from 1 to 2 metres to up to 700 metres high; and from centimetres to kilometers wide. Correlations have been found between earthquakes and mud volcano activity particularly if there is a major earthquake. This would explain why the island (thought to be due to a mud volcano) appeared off the coast of Pakistan this fall at about the same time as the large earthquake.