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Sinkholes Detection by AEM Method: a Case Study from Yucatan, Mexico
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, EAGE Workshop on Dead Sea Sinkholes – Causes, Effects and Solutions, Sep 2012, cp-310-00011
- ISBN: 978-94-6282-055-5
Abstract
A multi frequency helicopter electromagnetic survey was carried towards the north of Sian Kan, in Yucatan Mexico. In order to quantitatively asses the results, the water quality and determine the possible depths of the caves and tunnels, we processed and calibrated the data using a PhiBeta methodology to produce Conductivity Depth Images. Most structures that have been detected by AEM can be correlated with the location of dolines known from cave maps constructed by scuba divers. Some of these structures had not previously been mapped by divers but some others structures have been verified with dive expeditions following the airborne EM campaign. Hence it was possible to image an interesting network of karstic tunnels, which have formed at different geological stages i.e. at different depths, resulting in a halocline mix. Geophysics is also able to map the salt water intrusion, that can be seen as it pushes its way from the east past the coastline boundary and tends to migrate through preferential paths using the existing tunnels which are known to connect at sea at different locations and depths.