App2truedipG software

• Purpose
• History
• Method
  • Measurements
  • Computations
  • Input and Output
• Input
  • Input source
  • Input file
  • Input formats
• Output
  • Output destination
  • Output file
  • Output formats
• Plots
  • Plots destination
  • Statistics Plots
  • Section Plots
  • Example: Leg 180 Hole 1109D Core 47R section 2
• Acknowledgments
• References
  • How to refer to this program
• Downloading and Installing
• Revision history

Purpose

1. To restore strike and dip of planar structures measured as two apparent dips along known azimuth. Useful to process core structural measurements such as those made on ODP legs.
2. To plot the restored structure on a core section plot like that of ODP Visual Core Description templates (VCD); this allows to compare the restored measurements with the visual description sketch.
3. To displays statistics (histograms and roses).

History

This program was originally designed to restore strike and dip of planar structures measured on ODP Leg 176 cores. It relied on methods used during ODP Leg 147 and previous hard rocks legs where apparent dip measurements are either perpendicular or parallel to the saw cut and may be combined with a strike measurement. It was then modified to process non perpendicular apparent dip measurements during Leg 180. Graphic outputs were later added to allow a visual verification of the restored data.

Method

Measurements

1. apparent dip measurements, typically made along the saw cut or the core periphery, and
2. strike measurements, made in a section perpendicular to the core axis

1. two apparent dips with their directions, or
2. one apparent dip with its direction and one strike direction

Computations

The algorithm includes input validation and relies on the formula:

tan (Dipa) = cos (Azt-Aza) * tan (Dipt)

where

• Dipa is the apparent dip along the direction of azimuth Aza
• Dipt is the true dip along the dip direction of azimuth Azt

Input and Output

The program is designed with the idea of creating the input file by extracting the relevant data from a typical structural spreadsheet and of pasting back the computation results into the same spreadsheet. Alternatively, the input can be entered on the keyboard and the output displayed on screen: this is useful when only a few data need be processed.

Input

Input source

Input can be read

• either from keyboard (to compute a few values),
• or from an ASCII text file.

Input file

The file follows a standard structure with:

1. a standard 2 lines header where the title in the first line can be used to indicate the hole and core number, followed by
2. standard data lines

Exporting the input file from a spreadsheet requires specific procedures.

Input formats

When apparent dip measurements are either perpendicular or parallel to the saw cut, conventionally oriented E-W, the apparent dip direction can be represented by either of N, E, S, W. This results in the alphanumerical format (#1) detailed below. Non perpendicular apparent dip measurements require a numerical dip direction format, also detailed below (#2). Section plots require section identification to change page upon reaching a new section and feature depth. This results in an extension of the above formats into formats (#3) and (#4). As a consequence, four input formats are available:

1. Alphanumerical-2dips:
   the dip directions are given by the characters E, W, N, S
2. Numerical-2dips:
   the dip directions are given as numbers (in degrees)
3. Alphanumerical-section-depth-2dips:
   same as Alphanumerical-2dips but with section number and feature depth within the section
4. Numerical-section-depth-2dips:
   same as Numerical-2dips but with section number and feature depth within the section

These formats cannot be mixed in the same file. Corresponding data lines are detailed below.

1. Alphanumerical-2dips format

   There are 2 possible input data line format that correspond to two different combinations of measurements.

   • Case 1: two apparent dips

     • Give E or W dip first.
     • Do not put zero dip as first data.
     • Dip angles are in degrees.

   • Case 2: one apparent dip + one strike direction

     • Strike is given as second value and followed by a 'A' (meaning Azimuth data)
     • Strike should be chosen so that dip is to the right (if not, it will be corrected)
     • First dip data can be along E, W, N or S
     • Dip and strike angles are in degrees.
     
     

   Column:	1	2	3	4	Comments
   Type:	real	character	real	character
   Units:	degrees	none	degrees	none
   Case 1: two apparent dips
   Data:	apparent dip 1	dip direction 1	apparent dip 2	dip direction 2
   Range:	]0, 90]	'E','W'	[0, 90]	'N','S'
   acceptable data:					-
   	16	'E'	50	'S'
   	16	'W'	50	'S'
   	16	'E'	50	'N'
   	16	'W'	50	'N'
   	16	'W'	0	'N'
   rejected data:					explanation
   	16	'N'	50	'E'	the E-W data must be first
   	0	'W'	50	'S'	zero dip data should be entered either second, or as strike (as in case 2 below: 50 'S' 270 'A')
   Case 2: one apparent dip + one strike direction
   Data:	apparent dip 1	dip direction 1	strike	strike indicator
   Range:	]0, 90]	'E','W','N','S'	[-360, +360]	'A'
   acceptable data:
   	16	'E'	50	'A'
   	16	'W'	230	'A'
   	16	'S'	50	'A'
   	16	'N'	230	'A'
   	50	'S'	270	'A'
   data that will be corrected:					explanation
   	16	'W'	50	'A'	The strike will be corrected to 230

   Sample file: appdip.test.in1.txt

2. Numerical-2dips format

   The only restriction is not to put zero dip as the first data.

   Column:	1	2	3	4	Comments
   Type:	real	real	real	real
   Units:	degrees	degrees	degrees	degrees
   Data:	apparent dip 1	dip direction 1	apparent dip 2	dip direction 2
   Range:	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]
   acceptable data:					-
   	16	90	50	180
   	16	270	50	180
   	16	90	50	0
   	16	270	50	0
   	16	270	0	0
   rejected data:					explanation
   	0	270	50	180	zero dip data should be entered second

   Sample file: 1109D47R2.in2.txt

3. Alphanumerical-section-depth-2dips format

   There are 2 possible input data line format that correspond to two different types of measurements.

   • Case 1: two apparent dips

     • Section number is an integer
     • Depth is feature center depth within the section in cm within [0,150]
     • Give E or W dip first.
     • Do not put zero dip as first data.
     • Dip angles are in degrees.

   • Case 2: one apparent dip + one strike direction

     • Section number is an integer
     • Depth is feature center depth within the section in cm within [0,150]
     • Strike is given as second value and followed by a 'A' (meaning Azimuth data)
     • Strike should be chosen so that dip is to the right (if not, it will be corrected)
     • First dip data can be along E, W, N or S
     • Dip and strike angles are in degrees.
   
   

   Column:	1	2	3	4	5	6	Comments
   Type:	integer	real	real	character	real	character
   Units:	none	cm	degrees	none	degrees	none
   Case 1: two apparent dips
   Data:	section #	depth	apparent dip 1	dip direction 1	apparent dip 2	dip direction 2
   Range:	any	[0, 150]	]0, 90]	'E','W'	[0, 90]	'N','S'
   acceptable data:
   	1	50	16	'E'	50	'S'
   	1	80	16	'W'	50	'S'
   	2	10	16	'E'	50	'N'
   	2	110	16	'W'	50	'N'
   	2	140	16	'W'	0	'N'
   rejected data:							explanation
   	3	100	16	'N'	50	'E'	the E-W data must be first
   	3	130	0	'W'	50	'S'	zero dip data should be entered either second, or as strike (as in case 2 below: 50 'S' 270 'A')
   Case 2: one apparent dip + one strike direction
   Data:	section #	depth	apparent dip 1	dip direction 1	strike	strike indicator
   Range:	any	[0, 150]	]0, 90]	'E','W','N','S'	[-360, +360]	'A'
   acceptable data:							-
   	1	50	16	'E'	50	'A'
   	1	80	16	'W'	230	'A'
   	2	10	16	'S'	50	'A'
   	2	110	16	'N'	230	'A'
   	2	140	50	'S'	270	'A'
   incorrect data that will be corrected:							explanation
   	3	100	16	'W'	50	'A'	The strike will be corrected to 230

   Sample file = appdip.test.in3.txt

4. Numerical-section-depth-2dips format

   The only restriction is not to put zero dip as the first data.

   Column:	1	2	3	4	5	6	Comments
   Type:	integer	real	real	real	real	real
   Units:	none	cm	degrees	degrees	degrees	degrees
   Data:	section #	depth	apparent dip 1	dip direction 1	apparent dip 2	dip direction 2
   Range:	any	[0, 150]	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]
   acceptable data:
   	1	50	16	90	50	180
   	1	80	16	270	50	180
   	2	10	16	90	50	0
   	2	110	16	270	50	0
   	2	140	16	270	0	0
   rejected data:							explanation
   	3	130	0	270	50	180	zero dip data should be entered second

   Sample file: 1109D47R2.in4.txt

Output

Output destination

Output can be directed

• either towards the screen (to compute a few values),
• or into an ASCII text file (that can be imported into a spreadsheet).

Output file

The file follows a standard structure with:

1. a standard 2 lines header, followed by
2. standard data lines

Output formats

Data lines repeat the input followed by the computed strike and dip, and a explanation if a problem in the input data precluded computation. The strike is normalised so that dip is to the right, i.e. so that adding 90 degrees to it gives the dip direction. The fields are tab-delimited so as to facilitate importation and pasting the computation results into a structural spreadsheet. Four different output formats correspond to the selected input format. Corresponding data lines are detailed below.

1. Alphanumerical-2dips format

   Column:	1	2	3	4	5	6	7
   Type:	real	character	real	character	real	real	character string
   Units:	degrees	none	degrees	none	degrees	degrees	none
   Case 1: two apparent dips
   data line:	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike (***)	absolute dip	(**)
   Range:	]0, 90]	'E','W'	[0, 90]	'N','S'	[0, +360]	[0, 90]
   Case 2: one apparent dip + one strike direction
   data line:	1st apparent dip input	1st apparent dip direction input	strike input (*)	'A'	absolute strike (***)	absolute dip	(**)
   Range:	]0, 90]	'E','W','N','S'	[-360, +360]	'A'	[0, +360]	[0, 90]

   
   (*) : Eventually corrected so that dip is to the right
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right

2. Numerical-2dips format

   Column:	1	2	3	4	5	6	7
   Type:	real	real	real	real	real	real	character string
   Units:	degrees	degrees	degrees	degrees	degrees	degrees	none
   data line:	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike(***)	absolute dip	(**)
   Range	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]	[0, +360]	[0, 90]

   
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right

3. Alphanumerical-section-depth-2dips format

   Column:	1	2	3	4	5	6	7	8	9
   Type:	integer	real	character	real	character	real	real	character string
   Units:	none	cm	degrees	none	degrees	none	degrees	degrees	none
   Case 1: two apparent dips
   data line:	section #	depth	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike (***)	absolute dip	(**)
   Range:	any	[0, 150]	]0, 90]	'E','W'	[0, 90]	'N','S'	[0, +360]	[0, 90]
   Case 2: one apparent dip + one strike direction
   data line:	section #	depth	1st apparent dip input	1st apparent dip direction input	strike input (*)	'A'	absolute strike (***)	absolute dip	(**)
   Range:	any	[0, 150]	]0, 90]	'E','W','N','S'	[-360, +360]	'A'	[0, +360]	[0, 90]

   
   (*) : Eventually corrected so that dip is to the right
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right

4. Numerical-section-depth-2dips format

   Column:	1	2	3	4	5	6	7	8	9
   Type:	integer	real	real	real	real	real	real	real	character string
   Units:	none	cm	degrees	degrees	degrees	degrees	degrees	degrees	none
   data line:	section #	depth	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike(***)	absolute dip	(**)
   Range	any	[0, 150]	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]	[0, +360]	[0, 90]

   
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right

Plots

Plots destination

Two distinct executables direct plots

• either towards a window on the screen,
• or towards PostScript file.

Further details can be found in platform specific information for:

• MacOS X
• MacOS Classic
• Sun Solaris

Statistics Plots

Histogram and rose plots of computed strike and dip can be produced (or disabled) at run time.

Section Plots

These plots are meant to verify the data by comparing the computed fault traces along the E-W saw cut with those on Visual Core Descriptions (VCDs). They can be disabled at run time. They require data that include section index and depth (format #3 & 4 defined above). A new page is generated for each new section, which is detected by a changing section number.

The plot can represent the saw cut of

1. either the archive half of the core (E-W section with W to the right)
2. or the working half of the core (W-E section with E to the right)

1. VCDs used during Leg 180 (1109D47R2 sample)
2. VCDs used during Leg 209 (1268A16R1 sample)

Example: Leg 180 Hole 1109D Core 47R section 2

• Shipboard structural working half VCD (available in initial reports): 1109D47R2.TIF.
• Section plot of working half with VCD model#1 1109D47R2.sect.w1.pdf.
• Section plot of working half with VCD model#2 1109D47R2.sect.w2.pdf.
• Stastitics plot 1109D47R2.stat.pdf.

Acknowledgments

References

• ODP Initial Reports, Leg 147, Explanatory notes, structural geology, measurement of structures, pages 28-31
• ODP Initial Reports, Leg 176, Explanatory notes, structural geology, structural measurements, pages 14-15
• ODP Initial Reports, Leg 180, Explanatory notes, structural geology, structural measurements, pages 16-17
• ODP Initial Reports, Leg 209, Explanatory notes, structural geology, structural measurements, pages 10-11

How to refer to this program

If results obtained with this program are published, it would be appreciated that they refer to:

• Celerier, B. 2004. App2truedipG, Apparent to true dip restoration, http://www.pages-perso-bernard-celerier.univ-montp2.fr/software/dcmt/app2truedip/app2truedipg.html

Downloading and Installing

System independent: 11 files

1. App2truedipG documentation (this file))
2. Data files documentation
3. Sample input file format 1: appdip.test.in1.txt
4. Sample input file format 2: 1109D47R2.in2.txt
5. Sample input file format 3: appdip.test.in3.txt
6. Sample input file format 4: 1109D47R2.in4.txt
7. VCD model 1: 1109D47R2.TIF
8. VCD model 2: 1268A16R1.pdf
9. Sample section plot VCD #1: 1109D47R2.sect.w1.pdf.
10. Sample section plot VCD #2: 1109D47R2.sect.w2.pdf.
11. Sample stastitics plot 1109D47R2.stat.pdf.

System dependent: 2 executables and 1 ReadMe

Applications and documents for various systems

Computer	Processor	Operating System	Downloads	Read Me !
Macintosh	PPC	MacOS 7 - 9	app2truedip3.1-ps-ppc PostScript application app2truedip3.1-qd-ppc QuickDraw application	MacOS Classic versions
Macintosh	PPC	MacOS X.4 - X.5	app2truedip3.1-ps PostScript application app2truedip3.1-qdx QuickDraw application	MacOS X versions
Macintosh	Intel i86	MacOS X.4 - X.5, X.6 with Rosetta	app2truedip3.1-ps PostScript application app2truedip3.1-qdx QuickDraw application	MacOS X versions

• Direct access to the binaries archive

Revision history

• Version 3.0: 15 November 2004    Branch from App2truedip 2.1. Restructure menus and prepare plot additions.
• Version 3.1: 23 November 2004    Plots fracture traces on VCD and statistics.