关键词: 地震灾情点, 空间插值分析, 动态模拟

Abstract: Earthquake always happens in an instantaneous and abrupt way,and the aftermath of an earthquake is difficult to be expected.The earthquake fieldwork teams are very difficult to arrive at the earthquake-stricken site and to provide the relevant information in 2 hours after an earthquake breaks out.We usually call this period of time as the "black-box" period of earthquake.The M_S 8.0 Wenchuan earthquake caused extremely high damage and wide influencing range,and how to quickly obtain the information on the disaster situation is of vital significance to earthquake emergency commanding and disaster mitigation.Actually,in this time section,people in the quake-affected area may gain some local disaster information,but how to collect,analyze and process this disaster information,and to provide it as reference information to the decision-makers for disaster mitigation and relief are the important research interests in emergency commanding.Therefore,the National Headquarters for Earthquake Disaster Mitigation has established the earthquake disaster short-message-service experimental platform which is based on the public service number 12322 for disaster mitigation to enable the interactive link between the handsets or other wireless terminals of the disaster reporting personnel at the earthquake-stricken area and the backstage headquarters,and to carry on corresponding processing of the information gained to further shorten the "black-box" period.The basic concept of the earthquake disaster short-message-service fast report platform is to define the handset or other wireless message terminal users as the disaster reporter,after an earthquake occurs,the earthquake disaster short-message-service central management platform sends out the downward invitation short message to collect earthquake disaster situation firstly,and upon receiving this short message,the disaster reporting personnel report the disaster situation of his/her own area to the earthquake disaster short-message-service central management platform in a preset format.After receiving the reports,the central management platform will make the analysis and spatial location on the national map,and carry on the algorithmic analysis of these spots to simulate the regional spatial distribution of the disaster.The disaster situation collection and analysis process on this platform is a dynamic change process with the disaster situation data collected,reflecting the earthquake disaster distribution information dynamically.The article introduces the interpolation algorithm and the technical realization in the simulation of disaster spatial distribution based on the reported messages of disaster situation from discrete spots on the earthquake disaster report platform.The discrete disaster situation spot is defined as Dot(x,y,z),in which x is the longitude of the discrete disaster situation spot,y is the latitude of the discrete disaster situation spot,and z is the attribute information of the discrete disaster situation spot.The value of z is 1,2,3 or 4 respectively,1 expresses no shaking felt or shaking felt slightly;2 expresses shake felt strongly,but no damage caused;3 expresses damage caused,but no casualties;4 expresses severe damage and casualties.Through analyzing the characteristics of discrete disaster situation spot information,and by contrasting among several interpolation algorithms,we finally adopted the method which combines GIS spatial analysis with Thiesen space interpolation algorithm to carry on the areal interpolation analysis for the discrete spot.The concrete algorithm steps are:(1)using Thiesen polygon algorithm to carry on the division and the interpolation of the sampling site,and to set up a polygon;(2)regarding the z value,the Z value of the interpolation point distributing in the Thiesen polygon region is equal to Z value of the sampling site in this region;(3)revising the outer boundary of GRID image.The interpolation calculation usually creates a GRID image with rectangle outer boundaries,which does not conform to the actual disaster distribution.So,this article uses the BUFFER analysis as the geographical space analysis method to determine the boundary of the calculating region;and(4)revising the internal boundaries.Different local disaster situation distributions exist in the Thiesen polygon,the partitioning of different disaster regions is usually not very smooth,so revision is made to the internal boundaries by means of re-sampling.This article uses the nearest neighborhood method to carry on the re-sampling analysis and computation.Based on the above method and model,we develop the experimental system by ARCGIS and WebSevice technology.The system was applied to the Wenchuan earthquake to a certain extent.The paper presents the analysis results of the data collected up to 24:00,May 12,2008,and the results tally basically with the actual disaster situation.The above model and system can make dynamic analysis and simulation with the change of the disaster information collecting points,and thus can promptly reflect and determine,to a certain extent,the rough distribution of earthquake disaster and provide the relatively accurate disaster distribution information for the earthquake emergency commanding and disaster mitigation.

Key words: earthquake disaster spot, spatial interpolation analysis, dynamic simulation