What causes an earthquake
Answer (1)
Answer:Earthquakes are primarily caused by the sudden release of energy in the Earth's lithosphere that creates seismic waves. This energy release is most often due to the movement of tectonic plates. Tectonic Plate Movement: The Earth's outermost layer is divided into several large and small tectonic plates that are constantly moving, albeit slowly. These plates interact at their boundaries in three main ways: - Convergent Boundaries: Plates collide. One plate may slide under the other (subduction), creating deep ocean trenches and causing powerful earthquakes. Alternatively, they may crumple and uplift, forming mountain ranges (like the Himalayas) - Divergent Boundaries: Plates move apart. Magma rises from the mantle to fill the gap, creating new crust. Earthquakes here are generally smaller and more frequent - Transform Boundaries: Plates slide past each other horizontally. Friction builds up, and when it's overcome, the sudden movement generates earthquakes. The San Andreas Fault is a famous example The process involves the build-up of stress along fault lines (fractures in the Earth's crust). When this stress exceeds the strength of the rocks, they rupture, releasing the stored energy as seismic waves. The point where the rupture begins underground is called the focus (or hypocenter), and the point directly above it on the surface is the epicenter Other Causes: While tectonic earthquakes are the most common and powerful, other factors can also trigger seismic activity: - Volcanic Earthquakes: Movement of magma beneath volcanoes - Collapse Earthquakes: Subterranean collapses of caverns or mines - Explosion Earthquakes: Underground explosions (nuclear or chemical) - Induced Seismicity: Human activities, such as fracking and wastewater disposal, can sometimes induce earthquakes The severity of an earthquake is measured using the moment magnitude scale, which considers the size of the fault rupture and the amount of energy released. The effects of an earthquake can range from imperceptible tremors to catastrophic destruction, depending on the magnitude and proximity to populated areas
