Charles Richter developed his scale using the maximum amplitude (height) of the largest wave recorded on a Wood-Anderson torsion seismograph. It was originally designed only for shallow earthquakes in Southern California, using a base-10 logarithmic calculation to handle the wide ...
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Attenuation is the weakening of seismic waves as they move away from the source. This happens because the energy spreads over a larger area (geometric spreading) and is absorbed by the rocks (frictional heating). High-frequency waves attenuate faster than low-frequency ...
A tiltmeter is a sensitive instrument used to measure very small changes in the vertical level of the ground. It can detect the “bulging” or “tilting” of the Earth’s crust that often occurs when stress accumulates along a fault line ...
The Elastic Rebound Theory relies on rocks being brittle enough to “snap.” However, at depths above 300 km, the pressure and heat are so high that rocks should flow plastically rather than break. The existence of deep-focus earthquakes suggests a ...
Intraplate earthquakes occur away from plate boundaries, often on ancient faults or “failed rifts” (aulacogens) created millions of years ago. Although these rifts didn’t fully break the continent, they remain zones of crustal weakness that can reactivate under modern tectonic ...