Research Topic 1. Assessing the Current State of Practice in Seismic Hazard Analysis in South America (SA)
Participants
- Monica Arcila - Servicio Geológico Colombiano, Bogotá, Colombia
- Jaime Eraso - Servicio Geológico Colombiano, Bogotá, Colombia
- Victor Contreras - Universidad de Chile, Santiago de Chile, Chile
- Ruben Boroscheck - Universidad de Chile, Santiago de Chile, Chile
- Marlon Pirchiner - IAG/USP, São Paulo, Brazil
- Herbert Rendon - Fundación Venezolana de Investigaciones Sismológicas-Funvisis, Caracas, Venezuela
- Hugo Yepes – Instituto Geofísico/EPN, Quito, Ecuador
- Julio Garcia - GEM Hazard Team, GEM Foundation, Pavia, Italy (Coordinator)
Methodology
The first step was the consolidation of existing seismic hazard knowledge in the region. Seismic hazard studies (at national and regional level) were appraised for consistency and overall characteristics and many of them implemented into the OpenQuake-engine. Local experts helped to guide this process during a meeting held at the Colombian Geological Survey (CGS), Bogota, in July 2014 by sharing their knowledge and experiences of hazard modelling in their regions and identifying key issues and limitations.
The main outcomes of these discussions can be summarised as follows:
- The level of documentation available rarely allows an accurate reproduction of the procedure used for the construction of the models.
- Area sources are without question the commonest typology used to model seismicity occurrence without relevant distinctions between the different tectonic contexts (e.g. active shallow crust, subduction interface and in-slab).
- The quantity and quality of information needed for the parameterization of shallow fault sources in terms of geometry and seismicity occurrence discouraged their use within PSHA in the region.
- The selection of ground motion prediction equations (GMPEs) is scarcely documented, and the criteria used for choosing GMPEs unclear.
- A limited treatment of epistemic uncertainty.
Main Results achieved within RT1
A harmonized compilation for some of the recent national hazard models (see Table and Figures below) was created. This compilation demonstrates the need for a harmonized modelling of hazard at a continental level and was used as a starting point for the construction of the new hazard model for the South America continent.
List of PSHA models considered and/or implemented
The next Table and Figures summarise the models analysed and their main characteristics.
Region | Year | Authors/Institution | Source typology | Logic tree | Availability | Additional info |
---|---|---|---|---|---|---|
Contact person | Area/Grid/Fault | ERF/GMPE | ||||
Bolivia | 2013 | OSC / E. Minaya | YES/NO/YES* | NO/NO | NO | Unpublished, see details in OSC |
Brazil | 2015 | PSHAB /M. Assumpcao | YES/YES/NO | YES/YES | NO | See details in PSHAB |
Chile | 2014 | UC / R. Boroscheck | YES/NO/NO | YES/YES | NO | See details in Núñez et al. (2015) |
Colombia | 2010 | SGC / M. Arcila | YES/NO/NO | NO/YES | YES | Unpublished, more information in SGC |
Ecuador | 2011 | IGEPN / H. Yepes | YES/NO/YES | NO/YES | YES | Developed in collaboration with IRD and GEM |
Peru | 2015 | IGP / H. Tavera | YES/NO/NO | NO/NO | NO | Unpublished |
Venezuela | 2015 | FUNVISIS/ H. Rendon | YES/NO/NO | Under preparation by FUNVISIS | ||
Continent | 2010 | USGS / M. Petersen | YES/YES/YES | YES/YES | YES | Preliminary model developed by USGS |
Continent | 1999 | GSHAP / | YES/YES/NO | NO/NO | NO | Two projects: PILOTO and PAIGH |
- OSC: Observatorio San Calixto, La Paz, Bolivia
- PSHAB: Study group in Probabilistic Seismic Hazard Analysis in Brazil, several universities, Brazil
- UC: University of Chile, Santiago de Chile, Chile
- SGC: Colombian Geological Survey, Bogota, Colombia
- IGEPN: Instituto Geofísico de la Escuela Politécnica Nacional, Quito, Ecuador.
- IRD: Institut de Recherche pour le Développement, France
- IGP: Instituto Geofísico de Perú, Lima, Perú
- FUNVISIS: Fundación Venezolana de Investigaciones Sismológicas, Caracas, Venezuela
- USGS: U.S. Geological Survey
- GSHAP: Global Seismic Hazard Assessment Program
- GEM: GEM Foundation, Pavia, Italy
- PILOTO: Dimaté et al. (1999)
- PAIGH: Tanner and Shepherd (1997)
National PSHA models
National PSHA models considered within RT1: left) shallow crust zones, right) subduction zones [interface and in-slab]. For Chile and Brazil the main and most updated bibliographic references are cited (see Table above).
References
Dimate, C., L. Drake, H. Yepez, L. Ocola, H. Rendon, G. Grünthal, and D. Giardini (1999). Seismic hazard assessment in the Northern Andes (PILOTO project). Annali di Geofisica, 42(6): 1039–1055.Paper
Núñez, I., Boroschek R., Comte, D., Contreras, V. (2015). “Nuevo Peligro Sísmico para Chile”. Student: Ignacio Nuñez., Proceeding at XI Congreso Chileno de Sismologia e Ingenieria Sismica ACHISINA 2015, Santiago de Chile, 18-20 de Marzo, Chile. In Spanish.Prooceding
Petersen, M., S. Harmsen, K. Haller, C. Mueller, N. Luco, G. Hayes, J. Dewey, K. Rukstales (2010). Preliminary Seismic Hazard Model for South America. In the Proceeding of the International Conference “Homenaje a Alberto Giesecke Matto”.
Tanner, J.G. and J.B. Shepherd (1997): Seismic hazard in Latin America and the Caribbean, Volume I: Project catalog and seismic hazard maps, IRDC, Ottawa, 143 p.Report
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