The Most Typical Factors of a Destructive Earthquake Affecting the Environment (On Example of the 1988 Spitak Earthquake)

Abstract

Destructive earthquakes can have a certain impact on the environment, conditioned by both the strength of the earthquake and local conditions, especially at the level of urbanization and seismic risk and the organization of disaster zone recovery. Based on the investigation data of the 1988 Spitak earthquake (intensity 9-10 points by EMS-98, M=7.0) these impacts can be divided into two groups based on the destruction of buildings and structures, activation of geological processes, and earthquake zone recovery period. The first group includes the collapse of buildings, activation of landslides, rock falls, soil liquefaction and subsidence’s, and activation of other geological processes that lead to changes in the environment. Larger scale earthquakes may have significant impact on the environment. For example, more than 50% of destruction of urban areas (especially buildings), major landslides (millions of tons of mass), collapse of reservoir dams resulting in floods, damages to lifelines (especially the main water supply and sewerage system), etc. The second group includes human activities during the earthquake recovery operations: selection of places to accumulate rubble, creation of temporary residential areas for the homeless and new settlements and districts, construction of new structures and infrastructure (transport, industrial, agricultural, etc.) especially in non-urban areas, destruction of green areas, cutting of trees, use of new areas for keeping domestic animals or setting up households, etc.