Three basic types of magma: 1  Mafic or Basaltic-- SiO2 45-55 wt%, high in Fe, Mg, Ca, low in K, Na. 2  Intermediate or Andesitic-- SiO2 55-65 wt%, intermediate. in Fe, Mg, Ca, Na, K. 3  Felsic or Rhyolitic-- SiO2 65-75%, low in Fe, Mg, Ca, high in K, Na.
intensity noun [U]. âº the âquality of being âextreme in âstrength or âforce: Simone âsings with âemotional intensity. The âlight âhit us with such intensity that we âducked. âº art Intensity in a âwork of âart âdescribes the âstrength of the âcolor, âsound, âlight, or âfeeling. (Definition of intensity from the Cambridge Academic Content Dictionary Â© Cambridge University Press).
intensity. The intensity is a number (written as a Roman numeral) describing the severity of an earthquake in terms of its effects on the earth's surface and on humans and their structures. Several scales exist, but the ones most commonly used in the United States are the Modified Mercalli scale and the Rossi-Forel scale. There are many intensities for an earthquake, depending on where you are, unlike the magnitude, which is one number for each earthquake. See also Earthquake ABC.