earthquakes

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EARTHQUAKE BY ACHAL GOEL

INTRODUCTION : 

INTRODUCTION An earthquake (also known as a tremor or temblor) is the result of a sudden release of energy in the earth’s crust that creates seismic waves. AFTER AN EARTHQUAKE IN JAPAN IN 2004

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The earliest earthquake for which we have descriptive information occurred in China in 1177 B.C. Earthquakes in Europe are mentioned as early as 580 B.C The earliest known earthquakes in America were in Mexico in the late 14th century and in Peru in 1471 Earthquakes in History

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The San Francisco earthquakes of 1906 was one of the most destructive in the recorded history of North America The Alaska earthquake of March 27, 1964, was of greater magnitude than the San Francisco earthquake; it released perhaps twice as much energy and was felt over an area of almost 500,000 square miles.

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Where Earthquakes Occur : 

Where Earthquakes Occur The Earth is formed of several layers that have very different physical and chemical properties. The outer layer, which averages about 70 kilometers in thickness, consists of about a dozen large, irregularly shaped plates that slide over, under and past each other on top of the partly molten inner layer. Most earthquakes occur at the boundaries where the plates meet. In fact, the locations of earthquakes and the kinds of ruptures they produce help scientists define the plate boundaries.

SEISMOMETER:AN INSTRUMENT TO RECORD AN EARTHQUAKE : 

SEISMOMETER:AN INSTRUMENT TO RECORD AN EARTHQUAKE SEISMOMETER ALSO KNOWN AS SEISMOGRAPH IS USED TO MEASURE AN EARTHQUAKE.IT DOES SO ON THE RICHTER SCALE.

DISASTER CAUSED BY EARTHQUAKES : 

DISASTER CAUSED BY EARTHQUAKES EARTHQUAKE MAY RESULT IN THE FOLLOWING- DISEASE LACK OF BASIC NECESSITIES LOSS OF LIFE GENERAL PROPERTY DAMAGE ROAD AND BRIDGE DAMAGE

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AN EARTHQUAKE WITH MAGNITUDE 3 OR LOWER ARE MOSTLY NOT SO DANGEROUS BUT THOSE WITH MAGNITUDE 7 OR HIGHER CAUSE SERIOUS DAMAGE OVER LARGE AREAS.

CAUSES OF EARTHQUAKE : 

CAUSES OF EARTHQUAKE MOVEMENT OF TECTONIC PLATES WITHIN THE EARTH VOLCANIC ACTIVITIES LANDSLIDES MINE BLASTS NUCLEAR EXPERIMENTS

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An earthquake's point of initial rupture is called its focus or hypocenter. The term epicenter refers to the point at ground level directly above the hypocenter. Global earthquake epicenters 1963-1998

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STRUCTURE CAUSES OF AN EARTHQUAKE

VOLCANOES AND EARTH QUAKES : 

VOLCANOES AND EARTH QUAKES Earthquakes are associated with volcanic eruptions. Abrupt increases in earthquake activity activated eruptions at Mount St. Helens, Washington; Mount Spur and Redoubt Volcano, Alaska; and Mauna Loa, Hawaii. The location and movement of swarms of tremors indicate the movement of magma through the volcano. INTERESTING FACT A sudden increase in earthquake tremors signaled the beginning of eruptions at Redoubt Volcano in 1989-90.

TSUNAMI AND EARTHQUAKE : 

TSUNAMI AND EARTHQUAKE Countries most affected by the 2004 Indian Ocean earthquake The earthquake and resulting tsunami affected many countries in Southeast Asia and beyond, including Indonesia, Sri Lanka, India, Thailand, the Maldives, Somalia, Myanmar, Malaysia, Seychelles and others. Many other countries, especially Australia and those in Europe, had large numbers of citizens traveling in the region on holiday. Both Sweden and Germany lost over 500 citizens each in the disaster.

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DO’S AND DON’T’S DURING AN EARTHQUAKE : 

DO’S AND DON’T’S DURING AN EARTHQUAKE

DO’S DURING EARTHQUAKE : 

DO’S DURING EARTHQUAKE • Keep calm. • Stay away from glass windows, doors, almirahs, mirrors etc. • Stay away from falling plaster, bricks or stones. • Get under a table or a sturdy cot so that you are not hurt by falling objects. • Do not rush towards the doors or staircase. They may be broken or jammed. Remember the drop, cover & hold drill.

DONT’S DURING AN EARTHQUAKE : 

DONT’S DURING AN EARTHQUAKE • Do not crowd around damaged areas or buildings. • Do not waste water. It will be needed for fire fighting. • Do not move the seriously hurt people. • Wait for medical help to arrive. • Do not spread rumors. They lead to panic and worsen the situation

IF YOU ARE OUTDOORS AT THE TIME OF EARTHQUAKE : 

IF YOU ARE OUTDOORS AT THE TIME OF EARTHQUAKE • If open space is available nearby, go there. • Keep away from tall chimneys, buildings, balconies and other projections. • Do not run through streets; hoardings or lamps may fall on you.

AFTER AN EARTHQUAKE : 

AFTER AN EARTHQUAKE • Check if you or anyone else is hurt. Use first aid atleast on the cuts and bruises. • Keep the streets clear for emergency services. • Switch off all appliances like the refrigerator, TV or radio. Turn off the gas. • Wear shoes to protect your feet from debris. • A battery operated radio will help you to get important messages. • Be prepared for more shocks. These aftershocks always follow an earthquake.

PROTECTION AGAINST EARTHQUAKES : 

PROTECTION AGAINST EARTHQUAKES Consult qualified architects and structural engineers regarding your plan of construction of buildings In highly seismic zones don’t construct multistoried concrete houses . Instead use mud & timber as construction material. The cupboards & shelves should be fixed in the walls. This will protect them from falling on human beings during earthquakes All the buildings must have fire fighting arrangements