#p-wave compression

• Anaseism — A seismological phenomenon consisting of the initial upward or push movement of the ground at the reception point (at the seismic station) upon the arrival of the primary seismic wave (P-wave), indicating a compressional motion away from the hypocenter. This structural dynamic, opposite to kataseism, is essential for researchers in determining the focal mechanism of an earthquake and for understanding the type of tectonic fault activated.