Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

DATA BASES ON HISTORICAL SEISMICITY:STRUCTURE, QUALITY OF INFORMATION,AND APPLICATIONSA. D. GvishianiInstitute of Physics of the EarthAcademy of Sciences, Moscow, USSRWilbur A. RinehartNational Geophysical Data CenterNOAA, Boulder, CO 80303, USAABSTRACTThe earthquake data bases of the National Geophysical Data Center,National Oceanic and Atmospheric Administration, USA, and the Instituteof Physics of the Earth, Academy of Sciences, USSR, are described.Together, these two data bases form one of the largest collections of earthquakecatalogs in the world. Information on historical seismicity is asignificant part of this collection.The main files are regularly supplemented with new earthquake determinations,taking into account priorities of their quality. A significantproblem is verification and correction of errors in the computer data bases.To solve this problem, we have developed special logical algorithms. Usingthese algorithms, errors have been found in 10% of the records in thecomputer-readable earthquake catalogs. Some examples of applicationsof historical seismic data to earthquake-prone areas are given.1. IntroductionThis paper describes two approaches to the storage, updating, and application oflarge collections of computer-readable earthquake catalogs. The first approach wasdeveloped at the National Geophysical Data Center (NGDC), National Oceanic andAtmospheric Administration (NOAA), USA. The second approach was developedat the Institute of the Physics of the Earth (IPE), USSR. These Centers maintaincontact with each other and exchange data on a regular basis. They participatein joint research efforts in the fields of seismological data bases and optimizing thedata base structure for data applications.The seismological data base archived by NGDC in Boulder, Colorado, knownas the NOAA earthquake data base, is one of the largest collections of computerreadableearthquake catalogs in the world. This data base is distributed by magnetictape with a fixed record format of 86 characters. Events are arranged on the tapein either chronological or geographical order. It consists of the following 11 files:(1) Preliminary Determination of Epicenters; (2) worldwide historical catalogs; (3)California and W. Nevada catalogs; (4) regional catalogs of the USA; (5) regionalcatalogs of Alaska; (6) regional catalogs of Hawaii; (7) regional catalogs of Canada;(8) regional catalogs of Europe; (9) regional catalogs of USSR; (10) regional catalogsof Asia; and (11) unclassified, local and regional catalogs. This data baseHistorical Seismogramsand Earthquakes of the World131Copyright 0 19x8 by Academic Press, Inc.All rights of reproduction in any form reserved.