SEISMOLOGICAL CONSTRAINTS ON THE MOTION OF THE CENTRAL AMERICA FOREARC SLIVER
We have examined earthquakes along the Middle America trench to see whether this hypothetical translation is reflected in the earthquake activity along this convergent margin.
We found that, for thrust-faulting earthquakes (i.e., those which reflect convergence between the Cocos and Caribbean plates):
- Earthquakes mechanisms are similar from the gulf of Tehuantepec to Nicaragua.
- They show no strike-slip component.
- Earthquake slip vectors almost coincide with direction of plate convergence
- Trend of P-axes also coincide with plate convergence direction
Additionally, oblique plate convergence is small and not uniform.
These results lead us to suggest that:
- Oblique plate convergence is not the mechanism for earthquakes along the volcanic arc.
- The forearc sliver is probably not being detached from the Caribbean plate.
- It is likely that the forearc sliver continues into southeastern Mexico.