Active deformation of the Central Myanmar Forearc Basin: Insight from post-Pleistocene inversion of the Pyay Fault

Pyay sub-basin is located in the southern part of the Central Myanmar Forearc Basin, an elongate belt of en-echelon folds and thrust faults formed as a result of the hyper-oblique convergence of the India and Asia plates. Limited neotectonic studies suggest that the Pyay Fault is a major Pliocene inverted structure that trapped the hydrocarbons in Pyay sub-basin, where only sparse field-based observations are available to address the nature of very recent neotectonic processes. This study focuses on structural deformation related to active inversion of the Pyay Fault using field-based geological observations and interpretations of industrial seismic data. We map the ∼105 km long Pyay Fault, an east- dipping high-angle reverse fault with a significant dextral strike-slip component. The fault underlies the western limb of the major NNW-SSE- striking anticlinal ridge that forms the western margin of Pyay sub- basin. Growth strata within the Pliocene-Pleistocene Irrawaddy Formation, imaged in the shallow part (<1 km) of 2D seismic profiles, reflects the deposition of Pliocene-Pleistocene sediments synchronously with the inversion of the underlying Pyay Fault. In addition, uplifted fluvial terraces of the Ayeyarwady River on the hanging wall of Pyay Fault reflect the post-Pleistocene inversion of the Pyay sub-basin. This study suggests that the Pyay Fault is a prime example of active deformation of the Central Myanmar Forearc Basin which plays an important role in the basin evolution and an earthquake source potential of the Myanmar territory.

Abstract licence: CC BY-NC

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.