Hydrological Investigations of the Santo Domingo Basin, New Mexico Using ýElectromagnetic Soundings
Abstract
Transient electromagnetic (TEM) and magnetotelluric (MT) soundings made during the ýSAGE (Summer of Applied Geophysical Experience) program in 2006-2007 to assess the ýhydrologic environment in the arid environment of the Santa Domingo Basin, northern ýNew Mexico. Water wells in the upper 600 m allowed the comparison of the field data ýwith synthetic soundings derived from borehole resistivity logs. Conductive, clay-rich ýlayers of less than 20 ohm-m dominate the upper basin fill except where resistive, ýpresumably sand, layers of several hundred ohm-m are present. Only where the thickness ýof the resistive layers exceeds their depths can they be resolved by the electromagnetic ýý(EM) methods. Consequently, delineation of the highest quality aquifers is only possible ýusing EM if resistive layers are relatively thick. One- and two-dimensional inversion of ýthe TEM and MT data, respectively, allowed some estimates of the salinity and/or ýporosity of the thick, predominantly sand, resistive zones using Archie's law. Forward ýand inverse modeling facilitated sensitivity analyses to evaluate which modeled ýsubsurface features were required by the field data and which features were supported by ýborehole logs. EM imaging of thick, water-saturated resistive zones, where confined and ýlaterally extensive, reveal aquifers valuable both for their potable water and storage ýcapacity. ý
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMGP32A..08B
- Keywords:
-
- 0619 Electromagnetic theory;
- 0915 Downhole methods;
- 0925 Magnetic and electrical methods (5109);
- 1835 Hydrogeophysics