6.3 magnitude earthquake strikes Pakistan's coast
On early Wednesday morning, a strong earthquake (6.3 magnitude) struck the coast of Pakistan, according to the US Geological Survey (USGS). The earthquake occurred 23 kilometres southwest of Pakistan's coastal city of Pasni at 3.30 am. Pakistan is a part of the boundary where Indian and Eurasian tectonic plates meet, making the country prone to earthquakes.
An earthquake occurs when two blocks of the Earth's surface slip past one another resulting in shaking. The blocks' movement is caused by the sudden release of energy in the crust of the Earth creating seismic waves. The place below the Earth's surface where the quake starts is known as hypocenter; the location directly above the hypocenter, on the surface, is called epicenter.
The seismic activity or seismicity of an area refers to the type, size, and frequency of earthquakes experienced over a period. Observations from seismometers are used to measure the earthquakes. Richter scale is the most common standard of measurement for earthquakes.
Smaller earthquakes that occur in a location before a larger earthquake are called foreshocks; only some earthquakes have foreshocks. The larger, main earthquake is known as the mainshock. Smaller earthquakes that follow mainshocks are called aftershocks; they can continue for days, weeks, months or even years. Some earthquakes can be violent enough to toss around everything on the surface and destroy whole cities.
Low-intensity earthquakes with Magnitude 3 or lower are considered weak while those with Magnitude 7 or more potentially cause damage over larger areas depending on their depth. The shallower an earthquake, the more damage to the structures it causes on the surface.
Large earthquakes, with magnitude greater than 8 have struck the Earth very frequently since 2004. Scientists analyzed the record high earthquake rate and suggested the increase in seismicity was likely due to climatic change. They examined the global frequency of higher magnitude earthquakes during 1900-2011. Earthquakes with magnitude 8 and more were elevated since 2004 with a rate of 1.2-1.4 earthquakes per year.
Several geological processes are triggering the reactive seismic waves to create earthquakes, faults, trenches and subduction zones. According to the scientists, the Earth is badly cracked and fractured partly due to its geology and primarily because of the intense heat within its interior. Geological features like mantle plumes, tectonic plates, faults, vents, volcanic systems, etc. also try to regulate that heat resulting kinetic energy.
The biggest earthquake ever recorded had occurred in South Chile near Valdivia on 22 May 1960. According to the United States Geological Survey, it had a 9.5 magnitude on Richter scale; it caused over $500 million loss and claimed 1,500 lives. The deadliest earthquake ever with a magnitude 8 on the Richter scale occurred in China in 1556; it had claimed over 830,000 lives.
Dr. Behzad Fatahi of University of Technology Sydney's Geotechnical and Earthquake Engineering Department said, "no one in the world is safe." Fatahi said a series of high-magnitude earthquakes is expected to strike any moment along some of the major fault lines on Earth. He added 5-10 earthquakes with an intensity greater than magnitude 6 are overdue in the US, Mid-East, India, China, and Japan.
The Earth is reeling from large earthquakes from one end to another. For over a year now, there have been several massive earthquakes in the world, including those in Chile, Afghanistan, India, Nepal, Taiwan, Indonesia, Japan, Ecuador, Vanuatu, Myanmar, and Italy. Scientists say the longer geological fault lines (fractures or discontinuities on the Earth's surface) take to activate, the stronger the earthquakes strike.