- - 25th March 2021
"Fault Related Geohazard Awareness in Southern Trinidad; Structural Modeling, Thrust Sequencing, Plate Boundary Evolution, and Fault Reactivation"
Good Day Members,
You are invited to our next, Technical Lecture Series titled;
"Fault Related Geohazard Awareness in Southern Trinidad; Structural Modeling, Thrust Sequencing, Plate Boundary Evolution, and Fault Reactivation" by
> Mr. LEON J. ADEN: Bifrost Energy
Prediction of the existence and location of complex fault-propagation folding in southern Trinidad has long been difficult, owing to the limitations of seismic quality and flexural slip algorithms that assume layer parallel contraction, constant bed thickness, and line-length balance. Given these limitations, an experiment that used tri-shear modeling was carried out at the Penal-Barrackpore Field. Reasonable results were obtained that match general elements of published geologic cross-sections of the field. Given this outcome, the methodology was extended along the length of seismic line TD91-177. New insights into thrust sequence and a rationale for the existence and placement of blind thrust features have been made.
Using this method, out-of-sequence thrusting (OOST), where successive thrusting evolves toward the hinterland rather than the foreland, is required to honor the geometry of the known Intermediate and Underthrust segments of the Penal-Barrackpore Field. Further, known subsurface geology to the north of the field is consistent with continued OOST all the way to the Oropouche Field. It is noteworthy that a similar thrust sequence exists in eastern Venezuela, suggesting that OOST may be more common than we tend to think it is.
Placing these observations into an even larger regional context, the OOST package of thrusts in southern Trinidad is directly related to plate boundary deformation associated with the Warm Springs-Central Range Fault System. The integration of active mud volcanism (emergent and potentially non-emergent) with these thrust trends could lead to potential evidence for fault-related geohazard awareness that extends beyond the Central Range. While generally, low magnitude earthquake activity occurs within the Gulf of Paria and near the south coast of Trinidad, suggesting stress relief, onshore earthquakes are rare, suggesting stress build-up across onshore Trinidad.
Gravity modeling of the area surrounding the Piparo and Devil’s Woodyard mud volcanos illustrates the potential for using gravity to develop a more informed geometry of subsurface fluidized mud. Trinidad is fortunate that it has a large full tensor gravity survey capable of underpinning a potential project focused on mapping 3D mud volcanism in southern Trinidad. Integration of a mud volcanism mapping project with a spectrum of seismic-based structural interpretations across central and southern Trinidad may provide a basis for an expanded area where preparation for the impacts of active faulting and/or mud volcanism might be desired.