Seismic damage assessment
Introduction
Seismic risk is a measure that combines seismic danger with vulnerability and the possibility of damage caused by seismic movements in a given period. This concept should not be confused with seismic hazard, which measures the probability that a certain acceleration of the ground will occur due to seismic causes, collapsing houses and causing death or injury.
Seismic risk is influenced by the probability of a seismic event or earthquake occurring, the possible local effects of amplification of seismic waves, directivity, etc., the vulnerability of buildings (and institutions) and the existence of inhabitants and property that may be harmed.[1].
The seismic risk depends strongly on the amount and type of human settlements in the place. Although the potential seismic hazard is very high in Yakutat (Alaska), the seismic risk is small because it is a highly uninhabited region. On the other hand, the seismic danger is not so great in Managua, because there large earthquakes are not usually as frequent as in Yakutat, but the number of people who live there, the proximity to the faults,[2] and the type of construction, make the seismic risk very great; This is clear when comparing the number of victims, for both places.
Quantification of seismic risk
There is no single way to evaluate seismic risk, so different standards "Standard (technology)") and different authors work with different risk indices. A risk index (R) is a function computable from the seismic hazard (P), the seismic vulnerability (V) and the potential seismic damage (D), something like:.
Where:.
The risk is enhanced when the danger increases, or the vulnerability increases, or the potential damage increases, for this reason the function is taken as a monotonic increasing function in all its arguments. If the function is differentiable that implies:
• - Spain: Resolution of May 5, 1995, of the Secretary of State for the Interior, which provides for the publication of the Agreement of the Council of Ministers approving the Basic Planning Directive for Civil Protection against Seismic Risk.
• - Engineering and Seismic Risk Group of the University of Alicante.
References
- [1] ↑ Mayer-Rosa, D. (1986), Tremblements de terre. Origine, risque et aide. Comisión Nacional Suiza de la UNESCO y Comisión Nacional Suiza de Geofisica.
- [2] ↑ Langer, C., M. Hopper, S. Algermissen y J. Dewey (1974), "Aftershocks of the Managua, Nicaragua, earthquake of December 23, 1972". Bull. Seism. Soc. Amér., vol. 64, pp. 1005-1016.