On September 8, a magnitude 6.8 temblor earthquake struck Morocco, killing more than 2,100 people, making it one of the deadliest quakes in the region. This, however, pales in comparison to the scale of destruction caused by the magnitude 7.8 quake that hit Turkey and Syria on February 6 this year, in which 21,600 people perished.
There have been more devastating earthquakes around the world for centuries, claiming the lives of millions of people till date.
An earthquake is one of the most widely occurring natural phenomena, with its origins dating back to Earth’s prehistory. An earthquake is the shaking of the Earth’s surface, resulting from a sudden release of energy in its lithosphere that creates seismic waves. Earthquakes and related seismic activity range in intensity, from being very weak, to being violent enough to propel objects and people into the air, damaging infrastructure, and wreaking havoc across human settlements.
The Earth’s crust is composed of tectonic plates that constantly move, which results in them sometimes getting stuck at their edges due to friction. When the stress on the edge overcomes the friction, an earthquake occurs that releases energy in waves that travel through the crust and cause it to shake. There are certain areas where this phenomenon occurs more frequently.
The seismic activity of an area is the frequency, type, and size of quakes experienced over a particular period. The world’s greatest earthquake belt sits along the rim of the Pacific Ocean, where about 81% of the largest earthquakes occur, earning the region the moniker “Ring of Fire”. Since recorded history, countries such as the US, Japan, and Chile have witnessed several calamitous quakes here, which have also caused widespread tsunamis and volcanoes in their wake.
Measure and Mitigate
Globally, the US’ National Earthquake Information Center locates about 20,000 quakes annually (approximately 55 per day). An earthquake is primarily measured by an instrument called a ‘seismograph’, which produces a digital graphic recording of the ground motion caused by seismic waves, called a ‘seismogram’. A worldwide seismograph network detects and measures the strength and duration of seismic waves.
Meanwhile, earthquakes are classified into categories ranging from minor to great, depending on magnitude. The classification starts with ‘minor’ (between 3.0 and 3.9), related to mild tremors, and ends with ‘great’ (over 8.0), resulting in significant damage. An earthquake has one magnitude unit, but this measurement does not depend on the location of measurement.
Between 1935 and 1970, the Richter Scale was more commonly used to measure quakes, which was later replaced by the Moment Magnitude Scale since it better-supported tremor detection all over the planet.
With improvements in technology, earthquake response and mitigation have also improved over the years. While seismologists observe that it is not possible to predict quakes, it is necessary to preempt and prepare. Better communication has helped the public know about quakes quicker than ever before. Countries that are earthquake-prone have also introduced changes by identifying hazards, building safer structures, and providing education on earthquake safety, all in a bid to minimise fatalities.
Quakes are not exclusive to Earth, with the Moon and Mars also noticing similar tectonic events. Earthquakes help the Earth release its stored-up energy, which in turn keeps the planet in good shape. It’s all a part of Earth’s evolution.