visualizing seismic wave propagation peter van kekenuniversity of michigan jeroen tromp dimitri...

Visualizing seismic wave propagation

Peter van Keken University of MichiganJeroen TrompDimitri Komatitsch CaltechShalini VenkataramanNicholas SchwarzLuc RenambotJason Leigh University of Illinois at Chicago

American Geophysical Union, Fall 2003, ED31E-01

Seismology in intro geophysicsUniversity of Michigan GS420

• Elastic deformation/wave equation• Refraction, reflection• 1D earth structure• Earthquakes and seismograms• Tomography• Attenuation, anisotropy

• www.geo.lsa.umich.edu/~keken/420.html

From Shearer (1999)

PcP: average P velocity in the mantle

PcP

P w

ave

shad

ow z

one

shadow zone

PKIKP

PKIKP: averageP velocity of the Earth

From Shearer (1999)

Ideal: Develop a good understanding of seismic wave propagation

Greatly aided by improvements in:- data acquisition

- computational power- computer visualization

Courtesy ExxonMobil

Example: active source seismics

Examples: Global seismology

• Alan Jones: Seismic Waves– Seismic phases, seismograms– www.geol.binghamton.edu/faculty/jones

• Saadia Baker and Michael Wysession– Synthetic mantle shear waves, seismograms– Normal mode summation– http://epsc.wustl.edu/~saadia

01347121723Jo

nes:

sei

smic

wav

es

Saa

dia

and

Wys

essi

on

New approach: SPECFEM3D

• Spectral finite element code (Komatitsch and Tromp, GJI, 2002;

Komatitsch, Tromp and Ritsema, Science, 298, 2002

www.geoframework.org)

• ‘Complete’ model: allows introduction of

– Ellipticity, anisotropy

– 3D mantle and crustal structure

• Massively parallel computation – Linux PC clusters at Caltech, Michigan

• Challenging code for visualization– Irregular grid

– Massive amount of data: O(Terabyte)

50s lowpass filter 14/8/95 New Britain (Mw=6.7)

Quiz: Name the phases labeled A through F (white/red indicate positive amplitude only)

P S

Vanuatu, 26/11/99

Bolivia, 9/6/94

3D = GeowallGS420 Fall 2002

EVL Volume Rendering

• Use color and transparancy

(Alternative: PC based volume renderer HVR www.lcse.umn.edu)

5123 8 bit 5123 16 bit

Quiz: Name the phases labeled A through F

SK

PP

PKP

Love

PPS

ScPP

ScSP ScSS