NETSIM: A Computer Program for Simulating Detection and Location Capability ofRegional Seismic Networks

摘要

This report describes a computer program called NetSim that calculatessimulations of detection and location capability of seismic networks that include regional stations and arrays. These simulations are used to assess seismic network capability to monitor existing and proposed nuclear explosion test limitation treaties. The main advantage of NetSim compared to similar computer programs (e.g., NETWORTH and SNAP/D) is the incorporation of frequency dependence in the source model, noise estimates (for both primarily and secondary phases), attenuation estimates, and array gain estimates. This is important for simulating the monitoring capability of regional networks, since the dominant signal frequency of regional phases often varies substantially with epicentral distance. The report provides functional descriptions of the NetSim detection and location modules and sample runs for frequency-independent and frequency-dependent input parameters. The accuracy of location uncertainties computed using two methods that attempt to account for the effect of undetected phases is also investigated. These are the probability-weighted approach used in SNAP/D and a Monte Carlo approach that mimics the way location uncertainties vary in practice. Keywords: Computer programs; Modules(Electronics); Input/Output data; Computer program verification; Seismic data. (cp)