Assessment of social aspects of seismic hazard

This paper is intended to illustrate the applicability of the results obtained from the investigations of social aspects of seismic hazard of the Russian Federation (RF) through the example of the high-seismicity region – the Far Eastern Federal District (FED). Within the FED the comparison of the areas of various seismic zones as per regulatory maps of General Seismic Zoning dated 2016 (GSZ-2016) has been performed and population estimates for each zone have been obtained. For the first time population estimates for zones with increased seismic hazard – grades A, B and C as per GSZ-2016 – are provided. The data obtained may be used for the evaluation of additional risks for FED’s population.


Introduction
In terms of population, Russia ranks ninth in the world with 146.4 million people as of 01.11.2020 [1], while the distribution of the population is quite uneven. In general, RF with the exception of certain regions is not a highly seismic territory. Among the high-seismicity regions are: Northern Caucasus, Southern Siberia and the Far East, while the latest is characterized by the earthquake intensity of points >8-10 at epicenter as per 12-level macroseismic scale MSK-64 [2,3].
Unfortunately, to date seismologists cannot provide reliable information regarding the exact place and time of occurrence of future earthquakes; therefore, the most effective method to reduce the number of possible human casualties and material damage is to identify areas with varying degrees of seismic hazard and to perform corresponding earthquake-resistant construction in these territories [4-7, 8-10].

Data and method
Seismic zoning is an important element of the evaluation of seismic risks and hazard. Maps of General Seismic Zoning (GSZ) are the regulatory documents for performing design and construction in seismically active areas. The main purpose of seismic zoning is to assess the seismic hazard in the study area. Since the development of GSZ-97 map of the general seismic zoning of RF all calculations and schemes are based on the probability analysis of seismic hazard.
In 2016 a research work to create a new set of GSZ-2016 maps replacing GSZ-97 maps for RF has been completed [11][12][13]. The set of maps has been renewed in accordance with the requirements of its revision each 10 years. This research was being carried out since 2009 by specialists from many academic and industry institutes and organizations of RF. At first stage sets of maps GSZ-2012 [14][15][16]17] and GSZ-2014 [18] were composed which after discussion by the scientific community and updating with modified linear-domain source database including Crimea region [19] formed a basis for GSZ-2016 maps.  Technology of general seismic zoning, considering both GSZ-97 and GSZ-2016, is based on probabilistic analysis of seismic hazard, used in most countries located in seismically active regions, and determining the probability of occurrence and possible excess of the points of the calculated seismic effects within a given time interval.
GSZ-2016 set of maps ( Fig. 1-3) makes provisions of implementation of anti-seismic practices during the construction of facilities of various risk ratings. GSZ-2016 maps of grades A, B and C illustrate respectively 10%, 5% and 1% of the exceedance probability of the designated seismic intensity within 50 years (either way, 90%, 95% and 99% of their non-exceedance probability).

Result
The social aspect means the awareness of the population about the existing seismic hazard and its adaptation to possible seismic risks [19]. Social aspects of the estimation of seismic hazard are illustrated through the example of the Far Eastern Region of RF characterized by high level of seismicity [20].
The The study is based on GSZ-2016 A, B, C maps used in territorial planning, city zoning, architectural and construction design, construction, overhaul, reconstruction of infrastructure facilities, operation of buildings and structures of various risk ratings. Numbers of population [21] living in the zones of various seismic intensity as per GSZ-2016 A, B, C maps have been compared.

Conclusion
For the residents of the areas with a high seismic hazard, the risk will always occur, but it must be minimized and made acceptable in certain socio-economic conditions. To ensure the safety of the population during the construction of various structures and facilities with a higher risk level, it is necessary to take social aspects into account.
The data provided in this paper should be taken into account as additional information when planning the construction of certain objects in the region. The presented data make it possible to assess seismic risks and take them into account when ensuring the seismic resistance of specific construction objects. For the first time, the article presents data on the distribution of population density and zones of probable seismic intensity for the territory of the Russian Federation using the example of the Far Eastern Federal District based on GSZ-2016-A, B, C set of maps. Until now, no such assessments have been carried out.