Seismic wavefield visualization Michael S. Thorne Dept. of Geology & Geophysics, University of Utah

Methods: Finite Difference calculations SHaxi – (global, axi-symmetric, 2.5D) [authors: Gunnar Jahnke, Michael Thorne, Heiner Igel] Open Source: PSVaxi – (global, axi-symmetric, 2.5D) [authors: Gunnar Jahnke, Michael Thorne, Heiner Igel] Open Source: not available yet E3D – (Cartesian box, 2- or 3D) [author: Shawn Larsen - LLNL] Source: not open source

Methods: Generating snap shots (freeware tools) Generic Mapping Tools: 2D snapshots. POV-Ray – Persistence of Vision Raytracer: 3D snapshots Gunnar Jahnke used to generate cover art for Shearer’s new edition of Seismo textbook. Widely used in planetary science community. Tutorial on my webpage.

Methods: Generating animations File > Import > Folder as Frames… File > Export > Original Document Adobe ImageReady – Quicktime animations ImageMagick – gif animations >> convert –adjoin –delay 4 –loop 0 *.jpg movies.gif full instructions at: (see Lecture #8)

Methods: non-linear amplitude scaling scale = 0.25 DO J=1,NR B = val(J) A = (ABS(val(J)))**scale val(J) = sign(A,B) ENDDO  example fortran code. scales amplitudes stored in array val, preserves sign. true amplitudesscaled amplitudes

Teaching – headwaves (Head_waves.mov)

Teaching – point scatterer (Point_Scatterer.mov)

Teaching – scattering Random velocity perturbations A von Karman autocorrelation function with 1 km correlation length is used to construct the random media. 3% RMS Vp perturbations are applied to the model. (noscatter.mov) (scattering.mov)

Teaching – velocity anomalies (Low_Velocity_Circle.mov)

Global SH-wave animations – SHaxi (shinjuku.mov)

Global SH-wave animations – SHaxi (Ddoubleprime_interaction.mov)

Global P/SV-wave animations – Gunnar’s rendering (PSV3D.avi)

Global P/SV-wave animations – div/curl coloring (SKKS_undulations.mov)

Resources: All animations available at: Some software available at: Computing lectures at: Suggestions for additional animations: