Earthquakes: The Causes And Consequences

Our Earth’s Landscape is made of a variety of elements that then make the beautiful shapes and forms we see. To classify them for further study they are divided in to groups based on different characteristics that they have. After the recent Earthquakes in Pakistan, we decided to make people aware of the reasons why such events take place but for that, we need to understand the formation of the earth, then the causes and consequences of earthquakes can be put in perspective.

Earth’s landscape includes different varieties. It includes

• mountains, hills,
• plains, grasslands, moors, meadows
• ponds, streams, rivers, seas, lakes, oceans, coasts
• desert,
• forests, jungles, rainforests

Natural Disasters

There are a lot of natural disasters that caused destruction. There are some that we do not know about, some are a result of human interference with nature.

Some of the natural disasters include:

• Cyclones
• Hurricanes
• Tornadoes
• Sandstorm
• Snowstorm
• Volcanic eruption
• Earthquake
• Tsunami
• Floods

With growing human activity, an imbalance has been created in nature. Just like Ozone layer thinning due to temperature rise. Climate change has caused a lot of problems including the melting of glaciers, floods, polluted seas/oceans, sea life extinction, and much more.

Earthquakes

Earthquakes are the deadliest natural disasters that ever occurred. Anyone remembers the 2005 earthquake. Oooh! We can still feel the tremors whenever it is recalled, it felt like the earth is just like paper, which will be ripped into two parts. We saw that in areas of AJK where the earth was divided.

Causes of Earthquake

Just like an onion, the earth has four basic layers. They are:

• The crust-the thin outermost layer
• Mantle-next to the crust, it is much thick
• Outer Core- this is very hot (4400-5000 C)
• Inner Core- it is immensely pressured (temperature more than 5000 C)

(tectonic plates come in between mantle and outer crust)

The earthquakes happen when the tectonic plates (between the mantle and outer crust) are stuck on the edges.  Usually, the plates keep on moving, sometimes they get stuck. The places where they get stuck start building pressure. When the pressure gets strong, it causes sudden movement (shock waves) of the plate causing an earthquake. Sometimes there are foreshocks and aftershocks (before and after the major earthquake). They can be mild to extreme in intensity.

How are they measured?

The shock waves that travel in the ground are known as seismic waves. They are the strongest in the centre. How big an earthquake is-it is measured through seismic waves by using a seismograph. The intensity of an earthquake is measured by the Richter scale. The higher the number, the higher the intensity is. It can range from 3-9. It is nearly impossible to have earthquakes of 10 on Richter scales. This is due to the fault line.

Fault lines

Fault lines are the cracks on the crust where rocks have slid past each other. The biggest fault line is the Weber Deep in the Banda Sea (Indonesia).  The Himalayan region is also one of the major fault lines. Pakistan has many minor and 5 major fault lines. Of them, Chaman (Pakistan-Afghanistan) and Shyok Suture Zone (Gilgit-Baltistan) are the two major fault lines.

Can they be predicted?

This is an ongoing discussion, scientists are still researching the ways where the earthquakes can be predicted and there can be less damage.

Consequences

The effects of earthquakes can be very serious. It can include:

• Landslides
• Tsunamis
• Infrastructure damage
• Liquification
• Fires
• Surface ruptures

Deadliest Earthquakes in History

• Chile (1960) – 9.6
• Indian Ocean & Tsunami (2004) – 9.1
• Sichuan Earthquake (2008) – 7.9
• Haiti Earthquake (2010) – 7.0
• Japan Earthquake & Tsunami (2011) – 9.0
• Nepal Earthquake (2015) – 7.8

*Tsunami-Japanese word meaning ‘harbor wave’, is large waves caused by undersea disturbance or activities on coastal areas.

Deadliest Earthquakes in Pakistan

• Quetta (1935) – 7.7
• Balochistan (2013) – 7.7
• Balochistan (2013) – 7.7
• KPK & Kashmir (2005) – 7.6
• Ziarat (2008) – 6.4
• Islamabad (2015) – 5.1

These events are natural and no one with accuracy can predict the real impact of such events. It’s always better to be prepared for such scenarios especially in case of emergencies.

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