EARTHQUAKE

Earthquake is an intense rocking to and fro motion or the seismic vibration of the earth about an imaginary centre located far from where it occurs, resulting in waves of shaking that radiate outwards from the earthquake source. When stresses in the crust produced by this to and fro motion exceed the strength of the rock, it breaks along lines of weakness, either a pre-existing or new fault plane. The point where an earthquake starts is termed the focus or hypocentre and may be many kilometres deep within the earth. The point at the surface directly above the focus is called the earthquake epicenter.

Intense vibrations, or seismic waves, spread out from the initial point of rupture (the focus) like ripples on a pond. These waves are what makes the ground shake and can travel large distances in all directions. Near the focus, the waves can be very large, making them extremely destructive.

Magnitude scales can be used to describe earthquakes so small that they are expressed in negative numbers. The scale also has no upper limit.

Earthquake Magnitude Scale

Magnitude	Earthquake Effects	Estimated Number Each Year
2.5 or less	Usually not felt, but can be recorded by seismograph.	Millions
2.5 or less	Usually not felt, but can be recorded by seismograph.	Millions
2.5 to 5.4	Often felt, but only causes minor damage.	500,000
5.5 to 6.0	Slight damage to buildings and other structures.	350
6.1 to 6.9	May cause a lot of damage in very populated areas.	100
7.0 to 7.9	Major earthquake. Serious damage.	10-15
8.0 or greater	Great earthquake. Can totally destroy communities near the epicenter.	One every year or two

 

 

Recent earthquakes

(1) 2001: 20,000 dead, India

A massive 7.7-magnitude earthquake on January 26 struck the western Indian state of Gujarat, killing more than 20,000 people.

The quake flattened buildings across the state, with many fatalities in the town of Bhuj near the border with Pakistan.

(2)2003: 31,000 dead, Bam (Iran)

A 6.6-magnitude quake in southeastern Iran on December 26 destroyed the ancient mud-brick city of Bam, killing at least 31,000 people.

Nearly 80 per cent of Bam’s infrastructure was damaged and the desert citadel, once considered the world’s largest adobe building, crumbled.

(3) 2004: 230,000 dead, Southeast Asia

On December 26, a massive 9.1-magnitude earthquake struck off the coast of Sumatra, triggering a tsunami that killed more than 230,000 people throughout the region, including 170,000 in Indonesia alone.

Waves 30 metres (100 feet) high, travelling at 700 kilometres per hour (435 miles per hour), swallowed everything in their path.

(4) 2005: 73,000 dead, Kashmir

An October 8 earthquake killed more than 73,000 people, the vast majority in Pakistan’s North-West Frontier Province and the Pakistani-administered zone of Kashmir.

A further 3.5 million were displaced.

 

(5)2006: 6,000 dead, Java

On May 26, a 6.3-magnitude quake rocked the southern coast of the Indonesian island of Java, near the city of Yogyakarta, killing around 6,000 people.

More than 420,000 were left homeless and around 157,000 houses were destroyed.

(6) 2008: 87,000 dead, Sichuan

More than 87,000 people, including 5,335 school pupils, were left dead or missing when a 7.9-magnitude quake struck southwestern Sichuan province on May 12.

The quake caused outrage after it emerges that 7,000 schools were badly damaged, triggering accusations of shoddy construction, corner-cutting and possible corruption, especially as many other buildings nearby held firm.

 (7) 2010: 200,000 dead, Haiti

A magnitude 7 quake on January 12 devastated the capital Port-au-Prince and the surrounding region.

The quake separated the country from the rest of the world for 24 hours, killing over 200,000 people, leaving 1.5 million homeless and shattering much of Haiti’s frail infrastructure.

(8)2011: 18,500 dead, Japan

On March 11, Japan is struck by an enormous 9.0-magnitude earthquake, unleashing a towering tsunami.

Around 18,500 people are left dead or missing as the wall of water travelling at the speed of jet plane levels communities along the northeastern coast.

The ensuing meltdown at the Fukushima Daiichi nuclear plant blankets nearby areas with radiation, rendering some towns uninhabitable for years and displacing tens of thousands of residents.

(9)2015: 9,000 dead, Nepal

A 7.8-magnitude earthquake on April 25 struck central Nepal, triggering avalanches and landslides across the Himalayan nation, It destroyed schools and hospitals.

The quake kills almost 9,000 people and renders millions homeless. It also reduces more than a hundred monuments to rubble, including centuries-old temples and royal palaces in the Kathmandu valley.

(10) 2023: 45,000 dead, Turkey and Syria

On February 6, a 7.8-magnitude quake struck near the Turkish city of Gaziantep, close to the Syrian border.

The biggest quake in Turkey in nearly a century, which was followed by a 7.5 magnitude tremor, reduced entire neighbourhoods of cities in southeastern Turkey and the north of war-ravaged Syria to rubble.

ETECHNOW

SOURCES

(1)AFP (2) EURONEWS (3) WIKIPEDIA (4) BGS (5) USGS