Nicole Feldl and Roger Bilham, Great Himalayan Earthquakes and the Tibetan Plateau, Nature 9 Nov 2006
The original article will be accessible here after 9 May 2007.
This 12 page single-spaced document with embedded figures describes in considerable detail the modeling approach, and includes listings of data and model results. It also includes a brief description of files used as input to the boundary element program 3D-def coded by Ellis and Gomberg. This is available from Nature or from here in modified form to invert very large matrices (see below). Sample files are attached ready to be input into the code, which is provided as a .tar file for operation on an Apple unix terminal.
Click here to download a 6.7Mb powerpoint talk given in Erice that explains the method and results.
300map
The input file 300map is for 300-km-long unrestrained rupture with a total of 29 planes each divided into 50 segments along strike. The first two planes are a rupture fronting the Himalaya dvided into five segments along-strike and five elements down-dip, the first being a steep ramp and the second a gently dipping decollement. It outputs a map view of the surface strain (suffix .m300) and a segment displacement listing in a north-south line through the center of the rupture. Columns 2 and 3 after the line that starts "for each plane" indicate the start points (distance and depth) of each segment, and columns 5 and 9 indicate the length and dip respectively. The along-strike length of the interseismic driving condition is 3600 km and in this model each segment width is 56.25 km. All elements are freely-slipping (code 12) except the most northerly plane and last listed plane (segment 30 is code 10) which drives the system at 25 mm/year, or in the case of coseismic rupture with an imposed displacement of 25 m. The first two planes specified are the Himalayan rupture, the first plane representing a 45° north-dipping 5.7-km-long ramp-thrust that cuts the surface . If these planes are removed and the number of planes reduced from 17 to 15 in line 2, the file can be used to calculate pre-seismic displacements or interseismic velocities. Strain and displacement changes accompanying rupture can then be obtained by subtracting the two output matrices.
Section400
This is an input file to 3ddef (see details below) that produces a strain cross section with the suffix .i400. Length east west is 1700 km, width N/S is 500 km, and it has fewer segments to speed computation. Sixty four along-strike segments are placed beneath the southern plateau, reducing to thirty-two 72 km north of the locking line. As before the rupture consists of two planes each with 25 segments.
3ddef.tar
This is a tar file that when unpacked produces a folder with 14 files including an executeable 3ddef program compiled in Fortran 91which will run in the terminal mode on Apple computers. See the readme.first for a message from Ellis and Gomberg. The README file from Walter Szeliga lists the changes made to prevent matrix arrays from overflowing. Place the input files section400 or 300map in the folder 3ddef once it has been de-compressed. To run the program from the unix "Terminal" on Apple computers, change the directory to 3ddef [cd desktop/3ddef] then type ./3d and enter the appropriately named input file when prompted. The program will run in the background, but will be faster if no other tasks are running.