Microtremor measurements to identify zones of potential fissuring in the basin of Mexico

The potential for the apparition of fissures and cracks in the Basin of Mexico can be inferred from microtremor measurements. Most of the cracking in the basin occurs where there is a sharp gradient in the depth of the hard layer below the soft clay. It is well known that the depth of the hard layer...

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Bibliographic Details
Published inGeofísica internacional Vol. 51; no. 2; pp. 143 - 156
Main Authors Ovando-Shelley, Efraín, Lermo-Samaniego, Javier, Auvinet, Gabriel, Méndez-Sánchez, Edgar
Format Journal Article
LanguagePortuguese
Published Instituto de Geofísica, UNAM 01.06.2012
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Summary:The potential for the apparition of fissures and cracks in the Basin of Mexico can be inferred from microtremor measurements. Most of the cracking in the basin occurs where there is a sharp gradient in the depth of the hard layer below the soft clay. It is well known that the depth of the hard layer is related to the dominant period, T0, of the site by the relation T0=4H/ Vs, where H is the depth and Vs is the average shear-wave velocity in the clay. If Vs is assumed roughly constant then the gradient of T0 would reflect the gradient in depth. Thus, if we can measure T0 then we can relate it to the potential of cracking in the basin. Nakamura's technique provides a simple, fast, and inexpensive way to estimate T0, at least in the lake-bed zone. The manuscript validates this premise in San Lorenzo, Ixtapalapa, where cracking has been observed and estimation of H is available from geotechnical data.
ISSN:0016-7169