Modeling elastic stresses in long ridges with the displacement discontinuity method

Authors
Citation
Sj. Martel, Modeling elastic stresses in long ridges with the displacement discontinuity method, PUR A GEOPH, 157(6-8), 2000, pp. 1039-1057
Citations number
33
Categorie Soggetti
Earth Sciences
Journal title
PURE AND APPLIED GEOPHYSICS
ISSN journal
00334553 → ACNP
Volume
157
Issue
6-8
Year of publication
2000
Pages
1039 - 1057
Database
ISI
SICI code
0033-4553(200008)157:6-8<1039:MESILR>2.0.ZU;2-J
Abstract
Elastic stresses at ridges formed by (a) erosion and (b) volcanism are calc ulated here by the method of particular integrals with a displacement-disco ntinuity boundary element method. The two geologic scenarios require treati ng the far-field stresses in the analyses differently. For a continuous bod y, the elastic governing equation requires that the second partial derivati ves of the Vertical and horizontal far-field normal stresses with respect t o horizontal and vertical directions be defined throughout the solution dom ain. This constrains admissible solutions for continuous bodies in both two -and three-dimensional analyses. For example, if the horizontal far-field n ormal stress varies linearly with depth over any depth interval in a contin uous body, then it must be continuous and vary linearly over the entire ele vation range of the solution domain. This far-field stress distribution per mits the description of a ridge formed by erosion of the surrounding materi al. A discontinuous or a piecewise linear distribution of horizontal far-fi eld stresses does not yield admissible solutions for a continuous body but can apply to a ridge constructed by volcanism. Stresses induced by topograp hy in volcanic ridges will inhibit dikes from propagating to the surface, f avor the formation of near-surface magma chambers, and promote slope instab ility. The analyses demonstrate that topography and the extant tectonic str esses will not by themselves fully determine the stresses in a ridge; the g eologic history is also important.