Hi all! Welcome to our blog, Tektonesiana.
The name of Tektonesiana is derived from the word tectonics and Indonesia. Tektonesiana represents our ‘passion’ on tectonics of Indonesia.
We, Indonesian geologists who share the same interest, use this blog to post articles that represent our works. These articles have been presented in scientific meetings. Some of them also have been published in journals. We have many questions about tectonics of Indonesia, and we want to share them with you. Enjoy our blog!
View our list of publications
This is an abstract of a talk presented at American Geophysical Union, Fall Meeting 2011. Active deformation along the western margin of the present day Mentawai forearc basin appeared as anticlinal ridges. Beneath the anticlinal ridges, the deformation zone exhibits (1) main backthrust, as the upward continuation of the Mentawai Backthrust in forearc basin, (2) seaward verging imbricated thrusts developed in the accretionary wedge and (3) the landward verging thrust developed in the forearc basin. The landward verging Mentawai Backthrust zone and together with the Frontal Thrusts, formed the doubly vergent active tectonics in the Sumatra subduction system.
This article notes the structural features in the Mentawai forearc that can be interpreted as products of compression of the accretionary wedge and forearc basin sediments. Compressional phases since the Late Miocene initiated (a) the landward vergent foldthrust belt in the Mentawai Fault Zone (MFZ), (b) reactivation of seaward vergent imbricated thrusts in the retro-accretionary wedge, and (c) uplift of the accretionary wedge and some parts of the forearc basin. The authors interpret that the northwest part of the accretionary wedge underwent higher compression and tilting. The compression of the forearc is suggested to be controlled by the combination of the geometry and position of the continental backstop, and the subducting bathymetric high in the oceanic plate.
This is a note from an article that has been published in Geophysical Research Letters, 2011. An earthquake of Mw = 7.8 occurred on the 25th October 2010, SW of Pagai Island, Sumatra. The earthquake generated an unexpected very large tsunami on Pagai Islands with run‐up height of up to 8 m. Here we present seismic reflection and bathymetry images from the 2010 epicentral region acquired before the earthquake. The authors found that the frontal thrust is the main active fault in this region and might have ruptured up to the seafloor at 6 km water depth uplifting the water column and producing a large tsunami.
This article presents the interpretation of newly acquired high-quality industry-standard deep seismic reflection and swath bathymetry data to provide insight into the structural style and evolution of the Mentawai Fault Zone (MFZ). The structural style, lateral distribution and kinematics of the fault zone has been discussed related the development of forearc high thrusts and accretionary wedge mechanics. The implication of this fault zone to the coseismic rupture during slip of the megathrust is also discussed.