Earthquake Data Integration

GOCAD Instructions

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Earthquake Data Integration

• Earthquakes and Structural Geology

• Beach balls and other plots

• Using GOCAD

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Earthquakes and Structure

Location of faults Type of fault,orientation of fault plane

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Beach balls and other plots

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Beach balls and other plots

map

Dilational first arrival

Compressionalfirst arrival

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Beach balls and other plots

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Using GOCAD

• For integration with other data (topography, geologic sections, fault models, bore holes …)

• For 3d visualization

• see demo

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Using GOCAD

Tutorial user information:

use SSH to login to rupture

user: tutorialpw : ask George

rupture 01% cd beachballs/epslabX

u:\beachballs\epslabX\*

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Using GOCAD

Typical raw data of focal mechanisms

• Input for psmeca module of GMT plotting software: 33.75 -118.13 -10.86 220.00 75.00 -70.00 2.40 000 000 43732 Lat. Long. Depth strike dip rake Mag. Xmp Ymp Name

uses strike of nodal plane

• Output of FPFIT program:

810223 1921 4.93 33-30.23 116-46.57 0.95 1.40 19 0 19.0 0.09 0.2 1.6 c 255 80 160 0.00 12 0.08 0.74 0.00 15 33 20C* 0 Date Time Sec. Latitude Longitude Dept Mag A1 A2 A3 A4 h_e v_e M ddi dp rak A5 A6 A7 A8 A9 A10 A11 A12 EventID

uses dip direction of nodal plane

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Using GOCAD

Importing GMT style data into GOCAD:

rupture 85% cd gmt

• Convert geographic coordinates to UTM coordinates:

rupture 93% proj -r +proj=utm +zone=11 smb81_98.geo > smb81_98.utm

• Convert UTM file to GOCAD file:

rupture 105% /sger/tools/beachball.awk smb81_98.utm > smb81_98.gp

beachball.awk expects STRIKE

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Using GOCAD

More beach ball options:

rupture 85% cd gmt

• Produce larger beach balls:

rupture 105% /sger/tools/beachball.awk RADIUS=1000 smb81_98.utm > smb81_98.gp

The variable RADIUS defines the radius of a magnitude 1 focal sphere (default = 200).

• Produce nodal planes and P-T axes:

rupture 105% /sger/tools/nodals.awk smb81_98.utm > smb81_98.nod

You can use the variable RADIUS with nodals.awk as well.nodals.awk expects STRIKE.

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Using GOCAD

Importing FPFIT style data into GOCAD:

rupture 85% cd fpfit

• Convert FPFIT file to GMT style file:

rupture 118% /sger/tools/fpfit2geo.awk smb81_98.fps > smb81_98.geo

• Convert geographic coordinates to UTM coordinates• Convert UTM file to GOCAD file:

rupture 105% /sger/tools/beachball_ddir.awk smb81_98.utm > smb81_98.gp

beachball_ddir.awk/nodals_ddir.awk expect DIP DIRECTION

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Using GOCAD

Beach ball summary:

• beachball.awk usage:beachball.awk [RADIUS=meter] gmtfile > gocadfilegmtfile format: any number of lines containingX[m] Y[m] Z[km] strike dip rake magnitude 0 0 Name

• beachball expects strike, beachball_ddir dip direction

• nodals[_ddir].awk produces nodal planes/P-T axes, same usage

• use proj to convert geographic coordinates into utm

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Using GOCAD

Importing large EQ data sets in GOCAD:

rupture 85% cd mining

• Convert FPFIT file to GMT style file:

rupture 118% /sger/tools/fpfit2geo.awk smb81_98.fps > smb81_98.geo

• Convert geographic coordinates to UTM coordinates• Convert UTM file to GOCAD point set file:

rupture 144% /sger/tools/eq2vs.awk smb81_98.utm > smb81_98.vs

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Using GOCAD

Filtering large EQ data sets in GOCAD:

change property used for colors

Choose color map or make one (Edit)

Custom color map for rakeright-lateral

right-lateral

left-lateral

thrust sense

normal sense

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Using GOCAD

Filtering large EQ data sets in GOCAD (example):

change to date

choose color map rainbow1

edit Low and High clip values

make transparent to displayonly earthquakes in 1982

Use property regions to separateearthquakes by date, magnitude ..

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Using GOCAD

Filter with a GOCAD script and export to GMT style file:

Type in script

Or load file:gocadfilter.script

Convert smb81_98_mag3to beach balls