The Environmental Seismic Intensity scale 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. 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. 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 as ESI 2007. Like many other intensity scales, ESI 2007 uses the basic structure of twelve degrees of seismic intensity and is designed for application during field surveys immediately after the seismic event. However, the definitions of intensity degrees in ESI 2007 are based on the observation of distribution and size of environmental effects produced by an earthquake. This approach makes ESI 2007 a uniquediagnostic tool for the assessment of seismic intensity levels X to XII in sparsely populated and uninhibited areas where earthquake effects on people and built environment may not be easily observed. For intensity level IX or lower, the ESI 2007 scale is intended to be used as a supplement to other intensity scales. a) the Definition of intensity degrees on the basis of Earthquake Environmental Effects; b) the Guidelines, which aim at better clarifying i) the background of the scale and the scientific concepts that support the introduction of such a new macroseismic scale; ii) the procedure to use the scale alone or integrated with damage-based, traditional scales; iii) how the scale is organized; iv) the descriptions of diagnostic features required for intensity assessment, and the meaning of idioms, colors, and fonts. Since 2007, the scale has been applied to modern, historical and paleoearthquakes in the frame of the INQUA TERPRO Commission on Paleoseismology and Active tectonics. It is now available in ten different languages.
