Other fault networks globally may exhibit similar physical and statistical behaviours. Our favoured hypothesis is that system rupture behaviour is regulated by misoriented faults that occupy critical geometric positions within the network, as previously proposed for the 2010 El Mayor–Cucapah earthquake in Baja California. However, characteristic behaviour is more favoured probabilistically because ruptures initiating on individual source faults in the system are statistically more likely to cascade into multi-fault ruptures with larger amalgamated Mw (Mwmax = 7.1) than to remain confined to the hypocentral source fault (Mw = 6.3 to 6.8). Analysis of earthquake frequency-magnitude distributions indicate that a Gutenberg-Richter frequency-magnitude distribution for the near source region cannot be rejected in favour of a characteristic earthquake distribution. CSC modelling using the same criteria but initiating the earthquake on other faults in the network results in a multi-fault rupture cascade for five of seven scenarios. The observed rupture sequence is most successfully modelled if maximum CSC imposed by rupture of the hypocentral fault on to receiver faults exceeds theoretical threshold values of 1 to 5 MPa that are assigned based on fault slip tendency and stress drop analyses. Geodetic and seismologic data indicate this earthquake initiated on a severely-misoriented reverse fault and propagated across a structurally complex fault network including optimally-oriented faults. He later adapted the scale so that it could measure the size of earthquakes around the globe.We use Coulomb stress change (CSC) analyses and seismicity data to model the physical and statistical behaviour of the multi-fault source of the 4th September 2010 Mw7.1 Darfield earthquake in New Zealand. 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. Unlike the Richter and moment magnitude scales, it is not a measure of the total energy (magnitude. 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 The magnitude was 7 on the Moment Magnitude scale. Resembles vibrations caused by heavy trafficįelt by people walking rocking of free standing objects Haiti 2010 A powerful earthquake on 12 June 2010, was caused by the North American plate moving past. 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. Richter Scale reading of 2011 Tōhoku earthquake (it was followed by a tsunami)
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