OVERVIEW of /oldFTP/neotec/Shells/: =================================== Here you will find many files needed to create dynamic neotectonic models of the lithosphere (either global or local) with our thin-shell finite-element program Shells, as described in my on-line guide, http://peterbird.name/guide/foreword.htm There are also samples of input and output files from both "Earth2" and "Earth5" global modelling projects, from 1998 and 2007, respectively. Here is what each folder (or file) contains, in typical order of use: /OrbWeaver/ = interactive finite-element grid editor, written for DOS operating system. If you have Windows, you would probably be better off running the new OrbWin, which you can find in /oldFTP/OrbWin/. WorldMap.dig = simple global basemap of coastlines, allowing you to see where things are located. Use with both the F-E grid editor (OrbWin or OrbWeaver) and the graphical post- processor (FiniteMap or OrbMapAI). /OrbNumber/ = utility program to renumber the nodes of any Shells .feg grid file, in order to reduce bandwidth, reduce memory usage, and increase execution speed of Shells. Don't skip this step! /OrbData/ = utility program to assign nodal data (elevation, heat-flow, crustal thickness, mantle lithosphere thickness, [compositional density anomaly], [transient geotherm curvature] to each node in Shells .feg grid file. Requires several gridded-data (.grd) files; examples may be found in folders /Earth2/ and /Earth5/. /Earth2/ = sample input and output files (preferred model 2000-01) for the low-resolution global Shells model of Bird [1998]. /Earth5/ = Sample input and output files (preferred model Earth5-049) for the high-resolution global models of Bird, Liu, & Rucker [2008, J. Geophys. Res./Solid Earth]. /In_Depth/ = Excel spreadsheet to illustrate how Shells input parameters affect the geotherm and the vertical profile of deviatoric stress (for any desired strain-rate tensor) in a typical continent. (Note that this has not been updated to include the transient geotherm curvature that Shells 2006.08.29 now supports as an option.) /BCs_tool/ = Utility to compute boundary-condition velocities for edge nodes in a regional Shells model, assuming that you want to use a new or experimental Euler pole for one of the neighboring plates. If you just want model-PB2002 velocities for neighboring plates, then you don't need this tool; instead you can just use boundary-condition code "5" for each edge node in the boundary-conditions (.bcs) file, and that with the 2-letter plate identifier. (See examples in folder /Earth5/.) Shells.exe = Executable of Shells for 32-bit Windows (i.e., Windows 95, Windows 98, Windows ME, Windows NT, Windows 2000, Windows XP, Windows Vista). Will it work in 64-bit Windows??? Let me know, please! Shells.f90 = Fortran 90 source code. Read this as the ultimate answer to any questions about input parameters or algorithms. May also be compiled for operating systems other than 32-bit Windows (assuming you can supply or replace IMSL routines that solve the large banded linear systems). /OrbMapAI/ = Graphical program to provide maps of both input and output fields of any Shells model. Runs in text mode, producing an Adobe Illustrator .ai file as its product. (Note that most users would be better off with my newer mapping program FiniteMap, which you can find in folder /oldFTP/FiniteMap/. For example, OrbMapAI code has not been updated from global plate model PB1999 to PB2002.) /OrbScore/ = Utility program to compare predictions of any Shells model to actual data such as: *seafloor spreading rates, *fault slip rates, *geodetic velocities, *principal stress directions, *maps of historical seismicity, or *fast polarization azimuths of SKS arrivals. (The last data type is new with the 2006 version OrbScore2. Another new feature is that data can be weighted by geographic area during scoring, to reduce effects of highly concentrated GPS velocities in Japan, etc. Search the source code OrbScore2.f90 for text string, "CALL Perform_Weighting" to see where this happens; if you don't want area-weighting, then replace this call with new code that sets all the weigths for that data type to unity.) Several text files (.txt) in this folder explain the necessary formats for scoring data to be read by OrbScore. Samples of these scoring-data files may be found in both the /Earth2/ and /Earth5/ folders. RECENT CHANGES: =============== /oldFTP/neotec/SHELLS/ was reorganized 2007.10.05. At that time: *previous versions of the Shells source code and (Windows) executable were replaced by the 29 August 2006 version that was used by Bird, Liu, & Rucker [2008] "Stresses that drive the plates from below, I: Definitions, computational path, model optimization, and error analysis" {J. Geophys. Res./Solid Earth}. New features include: -Uses 52-plate model PB2002, not 14-plate model PB1999. -New boundary-condition codes for greater convenience: 4 = automatic look-up of plate affinity and velocity of cut-slab nodes in subduction zones of a global model. 5 = automatic computation of velocity of any neighboring plate, requiring only the 2-letter identifier of that plate in the PB2002 model. Automatically adjusts for the chosen velocity reference frame. (Note that old boundary-condition code 3 is now deprecated because results are not independent of the velocity reference frame in which the model is run!) -Option to include extra "boundary" [sic] conditions of fixed velocity at plate-interior nodes. This option must be used with caution and understanding! Please read paper cited above. -Improved reporting of torque components on each plate, in a new output file. (This new code may behave strangely if the user's plates do not coincide with PB2002 plates!) -Two new models of basal shear traction: (ICONVE = 5) in which the only basal shear traction is applied to the forearc of a subduction zone within the domain of the Shells model, by a subducting plate which is outside the domain. See also /oldFT/neotec/Forearc/ in this case. (ICONVE = 6) in which Shells reads the torque report file from a previous run, and computes basal shear tractions for each plate to reduce artificial point forces on plate interior nodes. With iteration, such artificial point forces can be replaced and removed in a final physical model. {For a complete record of changes to Shells, open the source code file Shells.f90 (or Shells.f90.txt) and search for the text string, "History of changes to Shells".} *Files related to the Earth5 (high-resolution global) models of Bird, Liu, & Rucker [2008, J. Geophys. Res./Solid Earth] are contained in a new folder, /oldFTP/neotec/Shells/Earth5/. *Files related to the Earth2 (low-resolution global) models of Bird [1998; J. Geophys. Res.] have been removed to folder /oldFTP/neotec/Shells/Earth2/. Note that it is no longer possible to replicate these runs with the current Shells, because Shells has been upgraded from plate model PB1999 to plate model PB2002. Best wishes! Peter Bird UCLA 2007.10.05; updated slightly 2010.09.09