Environmental Seismic Intensity scale Environmental Seismic Intensity scale The Environmental Seismic Intensity scale (ESI 2007) is a seismic scale used for measuring the intensity of an earthquake on the basis of the effects of the earthquake on the natural environment (Earthquake Environmental Effects). The international effort to develop a new scale of macroseismic intensity that would focus exclusively on environmental effects of earthquakes began in the early 1990s and was sponsored by the International Union for Quaternary Research (INQUA). After the final draft of the scale was approved by INQUA at its XVII Congress in Cairns, Australia, in 2007, the scale became officially known
Seismic anisotropy Seismic anisotropy Seismic anisotropy is a term used in seismology to describe the directional dependence of the velocity of seismic waves in a medium (rock) within the Earth. A material is said to be anisotropic if the value of one or more of its properties varies with direction. Anisotropy differs from the property called heterogeneity in that anisotropy is the variation in values with direction at a point while heterogeneity is the variation in values between two or more points. Seismic Anisotropy can be defined as the dependence of seismic velocity on direction or upon angle. General anisotropy is described