Earthquakes are one of the most destructive forces of nature, capable of causing immense destruction and loss of life in a matter of seconds. They can strike without warning, causing widespread damage and loss of life. But how do earthquakes work? What causes them, and how can we prepare for them?
One of the most significant risks from earthquakes is the damage they can cause to buildings and other structures. When the ground shakes, buildings can sway, and poorly constructed or unreinforced structures can collapse. In addition, earthquakes can trigger landslides, tsunamis, and other secondary hazards.
The Dance of the Plates
To understand earthquakes, we first need to understand the structure of the earth. The earth is made up of several layers, including the crust, mantle, and core. The crust is the outermost layer and is composed of several large plates that float on the mantle. These plates are constantly moving, driven by the flow of molten rock, or magma, in the mantle.
When two plates collide, they can create a fault or a crack in the earth’s crust. Over time, the pressure and stress from the movement of the plates can build up along the fault line. Eventually, this pressure becomes too great, and the rocks along the fault break and shift suddenly, causing an earthquake.
Such an earthquake is a sudden and violent shaking of the ground caused by the release of energy from within the Earth’s crust. When the plates move, they create a build-up of pressure along their edges, which is eventually released in a powerful seismic wave. This wave radiates outward from the epicenter, the point on the surface directly above the focus, or the point within the Earth where the earthquake originated.
Smaller earthquakes are known as aftershocks usually take place in the same general vicinity and on the same fault line as the main earthquake. They are brought on by the Earth’s crust’s shift in response to the primary shock. Days, weeks, or even months may pass after the primary earthquake before an aftershock occurs, and they might vary in size and frequency.
Aftershocks can occasionally be almost as powerful as the primary shock and result in more harm and injuries. After a big earthquake, it is crucial to remain alert and ready for aftershocks as they can complicate rescue and recovery efforts and amplify the first disaster’s effects.
How is it measured?
The severity of an earthquake is measured by its magnitude, which is determined by the amount of energy released during the quake. Magnitude is measured on the Richter scale, a logarithmic scale that assigns a number from 1 to 10 to each earthquake. A magnitude 1 earthquake is barely perceptible, while a magnitude 10 earthquake is almost unimaginable in its destructive power. The higher the magnitude, the more powerful the earthquake and the more destruction it can cause.
The Richter scale
The Richter scale is a logarithmic scale used to measure the magnitude of earthquakes. American seismologist Charles Richter presented it in his 1935 paper, where he called it the “magnitude scale”, and it remains the most widely used method for measuring the strength of earthquakes. The scale is based on the amplitude of the seismic waves produced by an earthquake, with each increase of one unit on the scale representing a tenfold increase in the strength of the earthquake.
One DATSinteresting! fact about the Richter scale is that it is not a physical measurement, but rather a mathematical calculation. It is also important to note that while the Richter scale is still widely used, it has some limitations. For example, it only measures the strength of an earthquake at the epicenter, and it does not take into account the duration or extent of the shaking.
A brief look back
Some historic earthquakes that have been measured on the Richter scale include the 1906 San Francisco earthquake, which had a magnitude of 7.9 [Source: Britannica], and the 1964 Alaska earthquake, which had a magnitude of 9.2 [Source: USGS]. The 2011 Tohoku earthquake in Japan, which triggered a massive tsunami that devastated coastal communities, had a magnitude of 9.1 [Source: IOC-UNESCO]. These earthquakes are just a few examples of the destructive power of seismic activity and the importance of understanding the Richter scale to help prepare for and mitigate the impact of earthquakes.
At the time of writing, the 2023 Turkey–Syria earthquake was a recent devastating seismic event that occurred on 6 February 2023. The earthquake, with a magnitude of Mw 7.8, struck southern and central Turkey and northern and western Syria, causing widespread damage across an area of approximately 350,000 km2 (140,000 sq mi). The epicenter was located 32 km (20 mi) west–northwest of Gaziantep, and the earthquake was followed by an Mw 7.7 aftershock at 13:24.
The earthquake had a maximum Mercalli intensity of XI (Extreme) and caused more than 51,800 confirmed deaths, with more than 45,000 in Turkey and more than 6,700 in Syria, as of 1 March 2023. The earthquake serves as a tragic reminder of the immense power of seismic activity and the importance of preparedness and emergency response in affected regions.
What can we do to prepare for earthquakes?
One important step is to ensure that our buildings and infrastructure are constructed to withstand seismic activity. This can involve retrofitting older buildings with earthquake-resistant features or designing new buildings with seismic safety in mind.
Bookcases, refrigerators, water heaters, televisions, and other large appliances and fixtures should be secured in your home. Place bulky and fragile items on low shelves. If there are structural problems with your house that could lead to its collapse during an earthquake, you might want to consider fixing them. Take into account buying earthquake insurance. Earthquake damage is not covered by a typical homeowner’s insurance policy.
In addition, it’s essential to have an emergency preparedness plan in place. This can include having an emergency kit with food, water, and other supplies, as well as knowing how to shut off gas, electricity, and water in the event of an earthquake.
Overall, earthquakes are a powerful reminder of the immense forces at work on our planet. By understanding how they work and taking steps to prepare for them, we can help minimize their impact and keep ourselves and our communities safe.
No matter how powerful an earthquake is, the best way to protect yourself is to be prepared. Make sure you have an emergency plan in place and that you know what to do when an earthquake strikes. Make sure you know where the nearest safe shelter is and that you have a supply of non-perishable food and water. By being prepared, you can help minimize the damage and loss of life caused by earthquakes.