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Earth Quakes Made By: AlishbaNadeemkhan.
Earthquakes • Some, but not all, earthquakes are related to volcanoes. For example, most earthquakes are along the edges of tectonic plates. This is where most volcanoes are too. However, most earthquakes are caused by the interaction of the plates not the movement of magma. • Most earthquakes directly beneath a volcano are caused by the movement of magma. The magma exerts pressure on the rocks until it cracks the rock. Then the magma squirts into the crack and starts building pressure again. Every time the rock cracks it makes a small earthquake. These earthquakes are usually too weak to be felt but can be detected and recorded by sensitive instruments. Once the plumbing system of the volcano is open and magma is flowing through it, constant earthquake waves, called harmonic tremor, are recorded (but not felt).
. On April 18, 1906, a disastrous earthquake struck San Francisco. Lasting less than a minute, it destroyed most of the city and killed 700 people. In 1976 the worst known earthquake killed over 650,000 people in Tientsin Province, China. Volcanoes and Earthquakes tells us about famous earthquakes and describes the natural forces that created them.
Volcanoes. • Volcanism, also spelled vulcanism, any of various processes and phenomena associated with the surficial discharge of molten rock, pyroclastic fragments, or hot water and steam, including Volcanoes, geysers, and fumaroles. Although volcanism is best known on Earth, there is evidence that it has been important in the development of the other terrestrial planets—Mercury, Venus, and Mars—as well as some natural satellites such as Earth’s Moon and Jupiter’s moon.
Ways to minimize loss of lives. • Ensure that poorly-constructed buildings are regularly maintained and reinforced to withstand earthquake vibrations. • A rescue team should always be ready. • There should be more drill practices in buildings and offices.
Earth quakes. • Made by: AlishbaNadeemkhan.
