Understanding Earthquakes: Causes, Measurement, and Prediction

Earthquakes are caused by the sudden release of energy in the Earth's crust, creating seismic waves. This release is usually due to tectonic plate movements, volcanic activity, or man-made explosions.

Seismologists use the Richter scale to measure earthquake magnitude. The scale is logarithmic, meaning each whole number increase represents a tenfold increase in measured amplitude and roughly 31.6 times more energy release.

Magnitude measures the energy released at the source of the earthquake. Intensity, on the other hand, measures the strength of shaking produced by the earthquake at a specific location.

There are primary (P) waves, which are compressional and travel fastest, and secondary (S) waves, which are shear and slower. Surface waves, like Rayleigh and Love waves, cause the most damage.

Ground motion prediction equations (GMPEs) estimate the expected ground motion at a site given the magnitude, distance, and other quake characteristics, crucial for engineering and hazard assessment.

The type of soil or rock can amplify seismic waves. Soft sediments can increase shaking intensity, while bedrock can reduce it. This is why similar earthquakes can cause different damage levels.

Despite advances in seismology, precise earthquake prediction remains elusive. Current research focuses on probabilistic seismic hazard analysis, which estimates the likelihood of certain magnitudes occurring within a region over time.

In the Amazon, there's a river so hot that it can actually boil. Geothermal heat, not volcanic activity, is the surprising source.