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| Titel |
Use of resistivity measurements to detect urban caves in Mexico City and to assess the related hazard |
| VerfasserIn |
R. G. Antonio-Carpio, M. A. Pérez-Flores, D. Camargo-Guzmán, A. Alanís-Alcantar |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 4, no. 4 ; Nr. 4, no. 4 (2004-09-30), S.541-547 |
| Datensatznummer |
250001819
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| Publikation (Nr.) |
 copernicus.org/nhess-4-541-2004.pdf |
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| Zusammenfassung |
| In the XIX century when Mexico City was much smaller than at present, there
was non-regulated mining of building materials in a region of tuffs
northwest of the city in an inhabited countryside. With the growth of the
city during the XX century, this region was increasingly populated and in
the 1970's many two-level bricks houses were built, without regard for
underground caves created by the earlier extractions. Some ground sinkings
in adjacent areas alarmed the residents who now are worried about this
permanent hazard. An association of residents contracted a private company
for a geophysical study in order to know the distribution of the caves.
Resistivity measurements were taken in the area to detect the caves in order
to alert city authorities. Resistivity data along most of the streets were
collected with the array pole-dipole that consisted of three grounded
electrodes. We performed 2-D dimensional inversions to the data in order to
get a 2-D resistivity image of every street. This is similar to a
resistivity cross-section of the ground but obtained from the inversion of
pole-dipole and Schlumberger resistivity data simultaneously. Using the
information of previous drills we modified our programming code in order to
perform constrained inversion and to get more accurate resistivity models in
agreement with the drills. From the resistivity models obtained for every
street it was possible to produce a map which shows the horizontal
distribution of the resistive bodies at a depth of 12m. These resistive
bodies show coherent alignments that seem to correspond with a distributions
of interconnected caves or tunnels used for extracting the sandy-tuffs. From
these kind of interpretation method it was intended to get a more accurate
horizontal distribution of the excavated areas in order to better know the
urbanized area affected and lead the authorities to remedy the area with
refill material. |
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