maavärinamehhanismi

Maavärinamehhanism is an Estonian term that translates to "earthquake mechanism" or "seismic source mechanism" in English. It refers to the physical process by which an earthquake occurs. This mechanism is primarily driven by the sudden release of accumulated stress within the Earth's crust.

The Earth's lithosphere is composed of tectonic plates that are constantly in slow motion. Friction between these plates, or within them, prevents them from sliding smoothly. This leads to the build-up of elastic strain energy over time. When this stored energy exceeds the strength of the rocks or the frictional resistance, a rupture occurs along a fault line.

The rupture propagates rapidly, causing the rocks on either side of the fault to shift and move. This sudden displacement releases the stored energy in the form of seismic waves, which travel outwards from the earthquake's focus (hypocenter). These waves are what we experience as ground shaking. The characteristics of the maavärinamehhanism, such as the type of fault movement (e.g., normal, reverse, strike-slip), the depth of the rupture, and the amount of slip, determine the magnitude and intensity of the earthquake. Studying the maavärinamehhanism is crucial for understanding earthquake behavior and improving seismic hazard assessments.