Peak ground acceleration design basis earthquake ground motion (DBEGM) is often defined in terms of PGA. Unlike the Richter and moment magnitude scales, it is not a measure of the total energy (magnitude, or size) of an earthquake, but rather of how hard the earth shakes at a given geographic point. The Mercalli intensity scale uses personal reports and observations to measure earthquake intensity but PGA is measured by instruments, such as accelerographs. It can be correlated to macroseismic intensities on the Mercalli scale but these correlations are associated with large uncertainty. See also seismic scale. The peak horizontal acceleration (PHA) is the
Frankston, Victoria in or near the suburb of Frankston have occurred in 1932, 1978, 1980, 2009 and 2014. The most recent, on 15 March 2014, measured 2.2 on the Richter magnitude scale. The largest, on 22 September 2009, measured 3.0 on the Richter scale. Olivers Hill is the most prominent elevation in Frankston which rises to 55 metres above sea level (180 feet) at its highest point in the suburb. Its origins date to approximately 415 to 360 million years ago. Its base is Mount Eliza Granite dating from the Devonian period, which was covered in lava tuffs in the Paleogene period.