He later adapted the scale so that it could measure the size of earthquakes around the globe. It was initially created to study a particular area in California, using the Wood-Anderson torsion seismograph, to compare the size of different earthquakes in the region. The Richter Magnitude Scale was developed in 1935 by Charles Richter. ![]() It is known today as the Modified Mercalli Intensity Scale. The Mercalli Intensity Scale was developed by Italian volcanologist Giuseppe Mercalli in 1884 and expanded to include 12 degrees of intensity in 1902 by Adolfo Cancani. The Richter scale is used to measure the magnitude of most modern earthquakes and allows scientists to accurately compare the strength of earthquakes at different times and locations. It is, however, used to compare the damage caused by earthquakes in different areas. The Mercalli Intensity Scale is only useful for measuring earthquakes in inhabited areas and is not considered particularly scientific, as the experiences of witnesses may vary and the damage caused may not accurately reflect an earthquake’s strength. This video explains how earthquakes are measured using the Richter and Mercalli intensity scales. Total destruction objects thrown in air, shaking and distortion of ground Some landslidesįew buildings remain standing, bridges destroyed. Ground badly cracked, many buildings destroyed. Ground crack, houses begin to collapse, pipes break Trees sway, some damage from falling objectsĬhimneys fall and some damage to building Resembles vibrations caused by heavy trafficįelt by people walking rocking of free standing objects ![]() ![]() The Mercalli scale is based on observed effects of an earthquake, while the Richter scale measures the amount of energy released during an earthquake.Īpprox. The following table provides a comparison between earthquake intensity levels as measured by the Mercalli scale and their approximate magnitude on the Richter scale. A base-10 logarithmic scale is obtained by calculating the logarithm of the amplitude of waves recorded by the seismograph. The Richter Scale measures the energy released by an earthquake using a seismograph. This process is experimental and the keywords may be updated as the learning algorithm improves.Richter Scale reading of 2011 Tōhoku earthquake (it was followed by a tsunami) ![]() These keywords were added by machine and not by the authors. The Pegasus Bay aftershock sequence is the most recent aftershock sequence of the 2010 September 3 UTC moment magnitude (M w ) 7.1 Darfield earthquake in. Moreover, extensive liquefaction (the conversion of soil into a fluid-like mass during an earthquake or other seismic event) caused ongoing ground movement leading to the undermining of many more foundations and the destruction of further infrastructure. The earthquakes severely damaged 80 per cent of the water and sewerage systems, with repairs continuing for many months. The earthquake flattened the downtown district, and damaged or destroyed over 180,000 homes. Although lower on the moment magnitude scale (MMS, now used to measure the size of earthquakes in terms of energy released instead of the Richter scale) than the September 2010 earthquake, the intensity and violence of the ground shaking during the February 2011 quake was measured on the Modified Mercalli Scale (used to measure the intensity and effects of an earthquake rather than just energy released) to be MM IX - among the strongest ever recorded globally in an urban area (Davidson, 2011). Striking closer to the city centre at midday, the February 2011 earthquake killed 185 people and injured another 2164. Centered two kilometres (1.2 miles) west of the town of Lyttleton and ten kilometres (6 miles) south east of the centre of Christchurch, the earthquake followed nearly six months after a 7.1 magnitude earthquake that caused significant damage across the Canterbury region, but no direct fatalities. At 12.51pm on February 22, 2011, a violent 6.3 magnitude earthquake struck the city of Christchurch - New Zealand’s second most populous city, and the largest city in the South Island.
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