Neotectonic Modelling of The Africa-eurasia Plate Boundary From The Mid-atlantic Ridge To Algeria
Abstract
In this work we use the plane stress or thin shell approximation to study the neotecton- ics at the boundary between the Eurasian and African plates, from the Mid-Atlantic ridge to Algeria. The Mid-Atlantic ridge, which is marked by its morphology, seis- micity and magnetic anomalies, is more sharply defined than the Africa-Eurasia plate boundary, which trends east-west and extends from the Azores triple junction into the Mediterranean sea. Seismological data show that its western and central segments are currently marked by a linear series of quakes indicating that the plate boundary is lo- cated in a narrow zone with dominant strike-slip motions. Further to the east, the plate boundary is widespread and the deformation spans over a much broader area. A set of models has been tested, in which we have considered different values of fault friction coefficient from 0.01 to 0.85. All models were scored by their correlations of predicted strain rate with actual seismic strain rate and by the mismatch between the predicted stress directions and data. We consider the ridge as a series of fault segments and we applied there the boundary condition of the relative North America-Eurasia velocity. Therefore, it permits us to use the compiled spreading rate data as a score for our models. Our preferred result is with a fault friction coefficient between 0.06-0.1. The maximum deformation is obtained along the Mid-Atlantic ridge, Terceira Ridge and northern Algeria. Also relatively high values are obtained along the plate boundary from Azores to Gibraltar and Betic-Rif thrust front. In contrast, the predicted neotec- tonic activity of the Atlas region is noticeably lower, with fault slip rates practically null.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.1745J