Evidence of ongoing crustal deformation related to magmatic activity near Socorro, New Mexico
Abstract
Recent leveling conducted by the National Geodetic Survey in central New Mexico provides new evidence of ongoing tectonic deformation associated with the Rio Grande rift. A 1980-1981 resurvey over suspected midcrustal and shallow magma bodies near Socorro, New Mexico, indicates continued uplift averaging 0.18 cm/yr between 1951 and 1980. Although this rate is somewhat smaller than that reported previously (0.34 cm/yr between 1912 and 1951), the new observations suggest possible systematic errors in the earlier surveys. Reanalysis of the earlier data gives an average rate of 0.23 cm/yr from 1912 to 1951, consistent not only with the new releveling observations but also with geomorphic evidence which indicates an average uplift rate of 0.18 cm/yr over the past 20,000 years. Thus the rate of uplift may be relatively constant. The new releveling measurements also confirm prominent zones of subsidence flanking the central uplift. Modeling the deformation, together with other geophysical observations, suggests that the movements in the Socorro area are likely associated with the 19-km-deep Socorro magma body. Although the details of magma movements are not well constrained, plausible models include flow of magma from the periphery toward the central magma chamber and flow from sources in the lower crust into the midcrust. Horizontal strain calculated for these models is generally consistent with the small strain reported from repeated trilateration surveys in the Socorro area. The Rio Grande rift is clearly an important site for future monitoring of crustal deformation.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- May 1986
- DOI:
- 10.1029/JB091iB06p06283
- Bibcode:
- 1986JGR....91.6283L
- Keywords:
-
- Crustal Fractures;
- Earth Crust;
- Geodetic Surveys;
- Magma;
- Tectonics;
- Mapping;
- New Mexico;
- Topography;
- Vertical Distribution;
- Geodesy and Gravity: Crustal movements;
- Tectonophysics: Continental tectonics