Variation of Young Oceanic Intraplate Energy Released With Lithosphere Age. Testing the East Pacific Rise and Its Converging to the Subduction Rivera Zone

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

We have estimated empirical relationships that associate the age of Pacific oceanic lithosphere with the seismic energy that is released on both flanks of the East Pacific Rise(EPR). The equations found were tested by comparing other empirical formulas based on lithospheric age, heat flow, and bathymetric depth published by previous works. The results of this study are consistent with the seafloor age ranging between 1 and 7 Ma throughout three perpendicular cross-sections. These three cross sections are located between the diverging plate boundary of the northern Pacific Ocean up to the subduction zone of western Mexico. The results allow inferring the mechanical boundary depth of mid-oceanic ridges and the subduction zones.

The distribution of seismic energy released within the limits of the Rivera and Pacific plates shows a gradual decrease from the ridge axis to the oceanic trench. However, an increase of seismic activity is recorded near the Mesoamerican Trench, where the Rivera Plate subducts under the North American Plate with an angle of ~46°. This anomaly is a consequence of the collision and deepening of the oceanic plate. Due to the homogeneity of this plate, it is possible to infer the projection of the isochrones in the subduction zone. Although the deepening of the mechanical boundary layer may be estimated from the square root function of the seismic energy, this brittle-ductile transition in the subduction zone deepens exponentially concerning recorded energy.

Presenting Author: Carlos A. Vargas

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