Interseismic uplift of anticlines above the Rakhine-Bangladesh Megathrust from ALOS-2 InSAR
Data files
Mar 01, 2024 version files 76.41 MB
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README.md
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Supplement_Material.zip
Abstract
The shallow portion of a megathrust represents the zone of first contact between two colliding plates, and its rheological properties control the seismic and tsunami hazards generated by the fault. Unfortunately, underwater geodetic observations are sparse due to the high cost of obtaining geodetic data, meaning limited information is available on the interseismic behavior of this part of most megathrusts. The Rakhine-Bangladesh megathrust offers a unique opportunity to probe the behavior of the shallow megathrust as it is the only ocean-continent subduction zone where the near-trench region is fully accessible on land. Here, we use observations from ALOS-2 wide-swath imagery spanning 2015 to 2022 to conduct an InSAR timeseries analysis of the overriding plate within Bangladesh and the Indo-Myanmar Ranges. We identify a narrow pattern of alternating uplift and subsidence associated with mapped anticlines but show that it cannot be explained by plausible rates of slip on the megathrust or other fault structures. Instead, we argue that the deformation is likely caused by active aseismic folding within the wedge above a shallow decollement. We show that estimates of the decollement depth derived from a viscous folding model and the observed anticline spacing are in agreement with previous seismic observations of the decollement depth across the fold belt. We suggest that the role of ductile deformation in the overriding plate in subduction zones may be more important than previously recognized.
README: Interseismic uplift of anticlines above the Rakhine-Bangladesh Megathrust from ALOS-2 InSAR
https://doi.org/10.5061/dryad.1ns1rn923
This file contains the dataset and MATLAB scripts of the manuscript for processing and analysis for Chong et. al., (2024), Interseismic uplift of anticlines above the Rakhine-Bangladesh Megathrust from ALOS-2 InSAR in JGR: Solid Earth.
Description of the data and file structure
Final_fitted_InSAR_velocity_masked.tif
- GeoTiff version of the final Line-of-Sight (LOS) velocities as shown in Figure 2 of the main paper
- LOS units are in meters/year
Textfiles folder
- This folder contains the Line-of-Sight (LOS) velocities and DEM in a textfile format for all the 3 selected cross-section transects:
- "_full.txt" indicates the original textfile without downsampling
- Central-Anticlines transect
- Chittagong transect
- Northern transect
- Textfiles of the starting parameters for the Bayesian Monte Carlo estimation for each of the dislocation models
- Textfiles of the optimized parameters for the Bayesian Monte Carlo estimation for each of the dislocation models
- Textfiles will consist of "_Optimized.txt"
- Header lines for the starting and optimized parameter textfiles are in the format below:
- Lon (°), Lat (°), Depth (km), Strike (°), Dip (°), Length (km), Width (km), Rake (°), Slip (cm/yr), Open (cm/yr), Notes
- Rake angles of the fault describes 0 = left-lateral; -90 = normal; 180 = right-lateral; 90 = reverse;
Scripts folder
- All relevant MATLAB scripts and the functions used to estimate the Bayesian Monte Carlo estimation for the dislocation models
GNSS_ITRF14_ref
- All GNSS stations with time-series textfiles that were converted from ITRF14 reference frame; include the velocities named "all_gnss_vel.txt".
- Format are in year; east velocities; north velocities; vertical velocities; units are described in textfile header
GNSS_Indian_ref
- All GNSS stations with time-series textfiles that have been converted from ITRF14 to the Indian reference frame; include the velocities named "all_gnss_vel_converted.txt".
- Format are in year; east velocities; north velocities; vertical velocities; units are described in textfile header