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"Tsunami warning center scientists usually measure an earthquake's "size" with the moment magnitude scale rather than the older but more famous Richter magnitude scale. The moment magnitude scale is better suited for measuring the "sizes" of very large earthquakes and its values are proportional to an earthquake's total energy release, making this measurement more useful for tsunami forecasting. Moment magnitude numbers scale such that that energy release increases by a factor of about 32 for each whole magnitude number. For example, magnitude 6 releases about 32 times as much energy as magnitude 5, magnitude 7 about 32 times as much as magnitude 6, and so on. This animation graphically compares the relative "sizes" of some 20th and 21st century earthquakes by their moment magnitudes (according to USGS/NEIC). Each circle's area represents its relative energy release, its color indicates its tsunami potential (see http://ptwc.weather.gov/ptwc/about_me...), and its label lists its moment magnitude, its location, and the year it happened. ----- Los científicos del centro de alertas de tsunamis miden el "tamaño" de un terremoto utilizando la escala de magnitud de momento y no otras escalas más antiguas y famosas como la escala de magnitud de Richter. La escala de magnitud de momento es más adecuada para medir el tamaño de grandes terremotos, y sus valores son proporcionales a la cantidad de energía liberada, lo cual hace esta medida de magnitud más útil para el pronóstico de tsunamis. Los números en la escala de magnitud de momento escalan de manera que la cantidad de energía liberada se incrementa 32 veces por cada número entero de diferencia. Por ejemplo, un evento con magnitud 6.0 libera cerca de 32 veces más energía que uno de 5.0, y uno de magnitud 7.0 libera 32 veces más energía que uno con magnitud 6.0, etcétera. Esta animación compara gráficamente el tamaño relativo de algunos terremotos ocurridos durante los siglos XX y XXI en término

"At least 75 killed and more than 400 injured after quake measuring up to 6.6 magnitude"

"Fears of local tsunami after fresh tremor measured at 7.8 strikes just south of port of Iquique"

"Researchers from the University of New South Wales (UNSW) explain how a recent discovery could help tsunami-prone areas reduce the impact of future disasters. Before the Japanese tsunami of 2011, the inland reach of such an event had been drastically underestimated. Soil samples from affected areas have proved to be the key to designing measures that can mitigate future disasters "

"According to news today on mbl.is there is now more magma in Hekla volcano then before the 2000 eruption. The news says that since the year 2006 there has been more magma in Hekla magma chamber then before the last eruption in the year 2000. This has not meant an eruption so far. Hekla volcano magma chamber have the depth of around 10 to 20 km. This means this inflation that is now taking place does not appear clearly on the surface, but changes are being measured by GPS system that Icelandic Meteorological Office has. This is also appearing on GPS instruments that geological department University of Iceland has. Even if inflation is now more in Hekla volcano then during the eruptions in the year 1991 and 2000 it does not mean that next eruption is going to be bigger. Since the size of the eruption depends on how much of the magma is mobile in the magma chamber. That amount remains unknown until eruption takes place and even then not all of the mobile magma might erupt."