Both seismic reflections and MT model confirm a southward subduction polarity with a progressive accretion history during the northward migration of the trench prior to the final collisional assembly of the crustal blocks along the Palghat Cauvery Suture Zone, the trace of the Gondwana suture in southern India.
Consequently, the timing of this major event is much younger than the initiation of subduction along the proto-IBM trench prior to 50 Ma.
This evidence implies that there were seismic gaps, regions of very low seismic activity, along the trench prior to these greatest earthquakes, and these gaps ruptured releasing large seismic moments.
The only issue left unresolved by the new AMS radiocarbon results is the chronology of a microlith of REM provenience (i.e., found in the disturbed sediments from profile collapse collected from the bottom of the 1960s trench prior to the 1988 89 excavation work).
Instead, they drew the superficial deduction that mere volume of shellfire was the key to reducing a trench line prior to an assault.
Following subduction initiation, a ridge crest approached the trench but probably went dormant prior to its subduction (120 125 Ma), after which the subducted oceanic crust became progressively older until about 95 Ma.
Deep trenches were etched into the wafer prior to the ELO growth, designed to interrupt lateral transport if it were occurring by diffusion along the surface.
This shear zone is interpreted as the result of a geodynamic switch in the Pacific subduction system that led to trench retreat / slab rollback just prior to the c. 115 Ma U-Pb ages of zircon in the normal sense shear zone.
There were no prior earthquakes in the trench-ward region of the aftershock area of the 1964 Alaska earthquake, but strong activity in the hypocentral area in the land-ward region could be found before the earthquake.
