Measuring earthquakes is a critical yet challenging task, as they strike suddenly and can sometimes be felt on a global scale. Earthquakes occur when the Earth's crust shifts abruptly, radiating seismic waves and causing shaking. These waves, along with other factors, help determine an earthquake's magnitude, ranging from 1 to 10 on the most common scale.
Contrasting magnitude, an earthquake's intensity refers to the strength of the shaking felt. It is classified using Roman numerals in the Modified Mercalli Intensity Scale, which is based on assessed damages and people's observations.
Today, scientists use the moment magnitude scale to more accurately measure earthquake strength and size. It improves upon the previously used Richter scale, according to the US Geological Survey.
The moment magnitude scale hinges on the earthquake's seismic moment, which factors in Earth's crust shift, the size of the cracked area, the force needed to overcome friction, and created seismic waves. Greater friction and a longer distance of shifting result in a larger moment magnitude.
Seismometers measure these waves with a pendulum and spring system. The shaking moves the pendulum, generating a graph called a seismogram. Magnitude ranks on a scale of 1 to 10, where each whole number increase signifies 32 times more energy released.
Lastly, considering intensity is vital because various factors, such as terrain, depth, and location, substantially impact the devastation caused by an earthquake.
