Science / Geology / P-Wave: Primary seismic waves. The fastest set of earthquake vibrations. They move through the Earth in compression and expansion motions (much like sound waves move through air). Called primary because they are the first recorded at a seismograph. Primary waves are able to travel through both solids and liquids.
Science / Geology / S-Wave: Secondary seismic waves. A seismic wave with a direction of vibration that is perpendicular to the direction of travel. S-waves are slower than P-waves and travel only through solids. MORE
Science / Geology / Magnitude: A measure of earthquake size, determined by taking the common logarithm base 10) of the largest ground motion observed during the arrival of a P-wave or seismic surface wave and applying a standard co MORE