HR: 0830h
AN: T31C-0854    [PDF]
TI: The New ILP Database of Quaternary Faults and Folds in South America
AU: * Costa, C H
EM: costa@unsl.edu.ar
AF: Universidad Nacional de San Luis, Departamento de Geologia Casilla de Correo 320, San Luis, 5700 Argentina
AU: Cisneros, H A
EM: cisneros@unsl.edu.ar
AF: Universidad Nacional de San Luis, Departamento de Geologia Casilla de Correo 320, San Luis, 5700 Argentina
AU: Machette, M N
EM: machette@usgs.gov
AF: U.S. Geological Survey, Geologic Hazards Team MS 966, Box 25046, Denver, Co 80225-0046 United States
AU: Dart, R L
AF: U.S. Geological Survey, Geologic Hazards Team MS 966, Box 25046, Denver, Co 80225-0046 United States
AB: As part of the International Lithosphere Program's Task Group II-2, we have completed the compilation of Quaternary faults and folds in South America and have established an Internet website for this data. The underpinning maps and reports have been released as electronic U.S. Geological Survey Open-File Reports (pdfs, see poster). The maps show the location, time, sense of slip, and activity rate of major earthquake-related features such as faults and fault-related folds. The maps are accompanied by descriptions of their Quaternary activity. The primary elements of the 10-year project are supervision and interpretation of geologic/tectonic information (Costa and Machette), data compilation (project participants), database design and management (Cisneros), and GIS input and management (Dart). A dozen experts in Quaternary faulting, neotectonics, paleoseismology, and seismology compiled the data: questions about individual faults or additions to the database should be directed to them. Prior to this project, digital maps of Quaternary faults did not exist for any of the South America countries, even though understanding the extent and character of active and older Quaternary faults are critical elements of seismic-hazards analysis. These new data will help extend the relatively short record of instrumental and felt seismicity that is the primary parameter for current seismic-hazard assessments in South American countries. Although some fault data were available for most of the countries (i.e., Venezuela), the degree of completeness varies as a function of the remoteness and vegetation cover (i.e., Brazil). A few faults such as the Bocono have had detailed investigations involving modern paleoseismic techniques. Other faults have been studied in some detail, usually in association with concerns about hazards to urban areas or the safety of critical facilities such as mining operations, oil-and-gas pipelines, or power-generating facilities. However, the general state of knowledge for active faults in South America is probably best described as incomplete and of a reconnaissance nature. With the exception of some historic surface faulting events, little is known about fault chronology and overall rates of fault activity-information that is difficult to acquire but critical to seismic-hazard assessments.
DE: 7221 Paleoseismology
DE: 7223 Seismic hazard assessment and prediction
SC: Tectonophysics [T]
MN: 2003 Fall Meeting