Earthquakes are tectonic shifts in the earth’s crust that cause massive rocks in the ground to suddenly break apart, shaking the ground and buildings and splitting the earth’s surface like a turtle’s back.
This causes mountain collapse, coastal collapse, ground slippage, landslides, rumblings (seismic booms), luminous phenomena, and movement of groundwater and hot springs. Earthquakes also cause sounds like thunder, artillery fire, or distant vehicle movement.
These sounds can be difficult to hear indoors, overlapping with the rattling of hanging objects in buildings, but are easily detected outdoors in the open.
Although you can’t feel or see an earthquake before it hits, unlike volcanoes, we have developed tools to measure its intensity.
This instrument, which measures the amount of energy and destructive force released during an earthquake, was developed by Charles Richter and Beno Gutenberg in the 1940s and is called the Richter seismograph.
The Richter scale is a ranking (numerical scale) of the magnitude or intensity of shaking.
Along with volcanoes, millions of earthquakes occur every year, most of which go unnoticed.
Globally, there are more than 100,000 earthquakes of magnitude 3.0 or greater per year, and about 100 earthquakes of magnitude 5.0 or greater that can cause significant damage to buildings.
About 10 of these earthquakes can be felt as shaking, and three to four are catastrophic.
Earthquakes are caused by the movement of plates, which can take many forms, such as volcanoes, but sometimes they are caused by other sources of seismic energy.
lates can be divided into three types of forces: downward tectonic forces, side-to-side tectonic forces, and tropical convection (heat-driven convection) inside the Earth that drags the underside of the plate.
Earthquakes occur in the less rigid, warmer, and more easily deformable part of the Earth (about 700 kilometers from the surface) called the lithosphere1) and also occur in the ocean.
The tidal waves generated by an earthquake in the ocean are called tsunamis, most notably the December 2004 tsunami in Southeast Asia, which caused massive loss of life and damage to infrastructure in the region.
China has been recording earthquakes since 1177 BC, and astronomer Zhang Hsiung built the world’s first seismograph in 132 AD, so it’s safe to assume that the country has suffered many earthquakes, large and small, since time immemorial.
An earthquake in Knossos, Crete, in 365 AD is said to have killed about 5,000 people, and the largest loss of life was in 1556 in Shaanxi, China, when 830,000 people were killed.
The 1811-1812 earthquake in New Madrid, Missouri, USA, uplifted some of the strata in the area and subsided others.
This caused the area to sink by 3 to 6 meters, creating a permanent lake.
In 1999, the year of the new millennium and the end of the world, there was an unusually large number of earthquakes, causing anxiety about what was really happening to the planet.
On August 17, 1999, an earthquake in Izmit, Turkey, killed 16,000 people and caused $25 billion in damage.
On September 21 of that year, a 7.6 magnitude earthquake struck Taichung, Taiwan, killing 2,474 people and injuring more than 11,000, with devastating economic consequences.
The November 12 earthquake in Düzce, Turkey, was the last major earthquake of the 20th century, with a magnitude of 6.3, killing 834 people and injuring 4,566.
On March 11, 2011, at 2:46 p.m., a magnitude 9.0 earthquake struck the Tohoku region of Japan, making it the fifth most powerful earthquake ever recorded on Earth.
The damage caused by earthquakes has as much impact on nature and human society as other types of disasters such as typhoons, volcanoes, and floods.
The destruction of buildings by earthquakes can lead to casualties, but even those who escape injury can lose their homes or jobs.
Earthquakes can also cause fires to break out simultaneously at multiple locations, which can be difficult to fight and can easily turn into catastrophic fires.
These fires can multiply the damage of an earthquake many times over.
In particular, national infrastructure such as power, telephone, water, and gas are severely damaged, and transportation facilities such as roads, railways, bridges, tunnels, airports, and port facilities are also severely damaged.
Transportation facilities can be disrupted, causing major disruptions in the supply of goods and services to society at large.
In addition, we can think of disruptions caused by the release of hazardous substances, rumors (such as the Great Kanto Disaster), and various accidents that accompany them.
Thus, earthquakes are not only the most violent of all natural disasters, but also the most geographically altering.
Earthquakes have long attracted the attention of humans because they are like wars that come without warning.