Earth Science - Earthquakes

Earthquake: A phenomenon where energy is released due to a large impact or fault slip underground. Magnitude: The total energy of an earthquake. Expressed to the first decimal place. Every 2-unit increase in magnitude multiplies the energy by 1000. In other words, a 1-unit increase in magnitude increases energy by 31.6 times, and a 0.2-unit increase approximately doubles the energy. Intensity: The measured strength at each observation point. Intensity is measured in whole numbers. Shaking is stronger closer to the epicenter and weaker further away. - Modified Mercalli Intensity Scale: Has 12 levels from I to XII. A concept that aligns intensity with earthquake damage. - Japan Meteorological Agency (JMA) Seismic Intensity Scale: Has 10 levels: 1-4, and 5-7 (strong/weak). A concept based on instrumental seismic intensity (seismic acceleration). Originally, there was no distinction between strong and weak, but as earthquakes became stronger, the difference in damage for the same level became larger, leading to the introduction of strong/weak distinctions starting from intensity 5.