DEPT GEOGRAPHY SECOND SEMETER

SUBJECT DISASTERPRESENTATION ALL ABOUT EARTHQUAKE PRESENT BY HABIB SHAH PRESENTED TO SIR SYED QASIM

UNIVERSITY OF BALOCHISTAN QUETTA

What is an Earthquake

The sudden shaking , trembling and vibration of Earth surface by sudden release of stress within the crust is know as Earthquake.

There are large earthquakes and small earthquakes. Large earthquakes can take down buildings and cause death and injury. While small Earthquake even sometime do not fell.

Aftershocks

An aftershock is an earthquake that occurs after a previous earthquake, the main shock. An aftershock is in the same region of the main shock but always of a smaller magnitude.

FOCUS AND EPICENTER

Earthquake generated at a point within the crust that is know as focus and the point on the Earth surface vertically above the focus that is know as epicenter of an Earthquake.

The line joining places of equal Earthquake intensity are know as seismic wave’s.

Seismic wave’s

Seismic waves are waves of energy that travel through the Earth's layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy.

The shaking is the strongest near the epicenter that is why the greatest amount of distraction is cause near the epicenter as a way from the epicenter.

P , S AND SURFACE WAVE’S

A wave is a vibration that transfers energy from one place to another without transferring matter (solid, liquid or gas). Light and sound both travel in this way.

When P and S wave’s reach to the Earth surface it convert into surface or long wave's which travel along the Earth surface.

The most violent and distraction is caused by long wave’s

What causes seismic waves?

Seismic waves occur from actions within the

Earth's core, including breaking and splitting

rocks, explosions and volcanic eruptions.

Seismograph

Seismographs record earthquakes. They record vibrations in the Earth, and they can detect both large and small earthquakes. Seismographs working together can also pinpoint the location of an earthquake.

Causes of an Earthquake

Volcanic eruption exert a great pressure and earthquake occurs in adjoining area. There is a deep relationship of causes and effect between these two phenomena, often earthquake occur at the time of volcanic eruption and sometimes earthquake cause volcanic eruption.

Plate tectonic Earthquake are mostly caused by tectonic forces. The greatest

intensity of seismic wave’s activity is found along convergent plate boundaries where oceanic plate are undergoing subduction. Strong pressure built up between the contact of the two plate and these are release by sudden fault slippage. that generate earthquake of large magnitude. The greatest earthquake expressing in japan, Alaska, Central America chili and other narrow zone else trenches and volcanic areas of pacific belt.

Effects of an Earthquake Landslide Earthquakes, along with severe storms, volcanic

activity, and coastal wave attack, and wildfires, can produce slope instability leading to landslides, a major geological hazard. Landslide danger may persist while emergency personnel are attempting rescue.

Fire Earthquakes can cause fires by damaging electrical power or gas lines. In the event of water mains rupturing and a loss of pressure, it may also become difficult to stop the spread of a fire once it has started. For example, more deaths in the 1906 San Francisco earthquake were caused by fire than by the earthquake itself.

Effects

Flood A flood is an overflow of any amount of water that reaches land. Floods occur usually when the volume of water within a body of water, such as a river or lake, exceeds the total capacity of the formation, and as a result some of the water flows or sits outside of the normal perimeter of the body.

However, floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes may cause landslips to dam rivers, which collapse and cause flood.

Effects Tsunamis A tsunami is a large ocean wave that is caused by

sudden motion on the ocean floor. This sudden motion could be an earthquake, a powerful volcanic eruption, or an underwater landslide.

The impact of a large meteorite could also cause a tsunami. Tsunamis travel across the open ocean at great speeds and build into large deadly waves in the shallow water of a shoreline.

Human impacts

An earthquake may cause injury and loss of life, road and bridge damage, general property damage, and collapse of buildings. The aftermath may bring disease, lack of basic necessities, mental consequences such as panic attacks, depression to survivors, and higher insurance premiums.

MAJOR EARTHQUAKE

One of the most devastating earthquakes in recorded history was the 1556 Shaanxi earthquake, which occurred on 23 January 1556 in Shaanxi province, China. More than 830,000 people died. Most houses in the area were destroyed and many victims were killed when these structures collapsed. The 1976 Tangshan earthquake, which killed between 240,000 and 655,000 people, was the deadliest of the 20th century.

The 1960 Chilean earthquake is the largest earthquake that has been measured on a seismograph, reaching 9.5 magnitude on 22 May 1960. Its epicenter was near Canter, Chile

 Earthquakes events in recent time.

The greatest earthquake in history occurred in Chile, 1960 May 22 . It had a magnitude of 9.5 and approximately 1,655 were killed, 3,000 injured, 2,000,000 homeless, and $550 million damage in southern Chile.

On Tuesday, January 12, 2010, another earthquake measuring 7.0 with an epicenter 16 miles west of Port-au-Prince, Haiti struck, killing over 100,000 people and affecting over 3 million others.

  An earthquake of magnitude 7.7 struck southwest Pakistan on Tuesday, 24th September 2013, killing more than 327 and injuring hundreds more. Reports indicated that houses were flattened

1935 Quetta earthquake. The 1935 Quetta earthquake occurred on 31 May between 2:33 am and 3:40 am at Quetta, Baluchistan, British Raj (now part of Pakistan). The earthquake had a magnitude of 7.7 Mw and anywhere between 30,000 and 60,000 people died from the impact.

Preparing for an Earthquake

Government Authorities need to educate people about earthquake prone

areas and fault lines in the country. People must also be educated about what earthquakes are and how to respond to them when they occur.

Proper building permits and approvals must be given before people build in these areas.

Governments must ensure, schools and shelters, and emergency command that facilities like fire and police stations, hospitals posts are working well and prepared to deal with an emergency. . In many countries, these facilities are legal requirements.

Preparing for an Earthquake

Individual Know your environments and buildings. It is important that you know where you live and

where you visit often. If this is an earthquake prone region, be sure you know about your building (home, school, work places) always keep in mind what you can do if an earthquake starts.

During an earthquake, try to get away from objects that will fall or break. Run for cover under a sturdy piece of furniture.

Move into the open if this is possible. Go out of the building if possible, as the building can cave in.

THE END