Boletín de la Sociedad Geológica Mexicana
versão On-line ISSN 1405-3322
MONTALVO ARRIETA, Juan Carlos; RAMOS ZUNIGA, Luis Gerardo; NAVARRO DE LEON, Ignacio e RAMIREZ FERNANDEZ, Juan Alonso. An approximation to the seismic regionalization in the state of Nuevo León, based on the propagation velocities of cutting waves and geological evidence. Bol. Soc. Geol. Mex [online]. 2011, vol.63, n.2, pp.217-233. ISSN 1405-3322.
This paper presents the first seismic regionalization map for Nuevo Leon state, at a scale of 1:250 000. It was made using geological information and P and S wave propagation velocity data. Seismic refraction methodology was used to obtain the wave velocity propagation. A total of 708 profiles were made on different geologic units that are included in the Nuevo Leon state type-lithological column. Outcrops on which the profiles were carried out include sedimentary, igneous, and metamorphic rocks, and Quaternary deposits. The generation of the seismic site conditions map is based on site effect codes, as proposed by the National Earthquake Hazards Reduction Program (NEHRP, U.S.A.), from VS30 determination and its correlation with lithological information. The regionalization map using VS30, has revealed that A (VS30 > 1500 m/s), B (760 < VS30 ≤ 1500), and C (360 < VS30 ≤ 760) class sites predominate in the study area. Areas characterized by alluvial material show lower values of VS30 (560 m/sec), whereas consolidated rocks, for example, those that constitute the Mesozoic sequences, display high seismic wave velocity propagation values (VS30 = 1200 - 3500 m/s). The results obtained in this work provide a first approximation of the seismic response of shallow materials in the state, whose use is important in the land use planning, urban development and for the calculation of seismic risk and other geological perils, particularly for areas with historical evidence of seismic activity, but with little or no seismic instrumentation.
Palavras-chave : Seismic refraction profiles; VS30; Northeast Mexico; seismic site effects; intraplate seismicity.