Velocity-porosity relationships in oceanic basalt from eastern flank of the Juan de Fuca Ridge: The effect of crack closure on seismic velocity

Takeshi Tsuji, Gerardo J. Iturrino

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

To construct in situ velocity-porosity relationships for oceanic basalt, considering crack features, P- and S-wave velocity measurements on basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge were carried out under confining pressures up to 40 MPa. Assuming that the changes in velocities with confining pressures are originated by micro-crack closure, we estimated micro-crack aspect ratio spectra using the Kuster-Toksöz theory. The result demonstrates that the normalised aspect ratio spectra of the different samples have similar characteristics. From the normalised aspect ratio spectrum, we then constructed theoretical velocity-porosity relationships by calculating an aspect ratio spectrum for each porosity. In addition, by considering micro-crack closure due to confining pressure, a velocity-porosity relationship as a function of confining pressure could be obtained. The theoretical relationships that take into account the aspect ratio spectra are consistent with the observed relationships for over 100 discrete samples measured at atmospheric pressure, and the commonly observed pressure dependent relationships for a wide porosity range. The agreement between the laboratory-derived data and theoretically estimated values demonstrates that the velocity-porosity relationships of the basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge, and their pressure dependence, can be described by the crack features (i.e. normalised aspect ratio spectra) and crack closure.

Original languageEnglish
Pages (from-to)41-51
Number of pages11
JournalExploration Geophysics
Volume39
Issue number1
DOIs
Publication statusPublished - Oct 1 2008
Externally publishedYes

Fingerprint

crack closure
seismic velocity
basalt
ridges
crack
aspect ratio
porosity
confining pressure
microcrack
confining
cracks
atmospheric pressure
P-wave
wave velocity
effect
S-wave
velocity measurement
P waves
pressure dependence
S waves

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geology

Cite this

Velocity-porosity relationships in oceanic basalt from eastern flank of the Juan de Fuca Ridge : The effect of crack closure on seismic velocity. / Tsuji, Takeshi; Iturrino, Gerardo J.

In: Exploration Geophysics, Vol. 39, No. 1, 01.10.2008, p. 41-51.

Research output: Contribution to journalArticle

@article{36b0dd737d884819a7543fefffada82d,
title = "Velocity-porosity relationships in oceanic basalt from eastern flank of the Juan de Fuca Ridge: The effect of crack closure on seismic velocity",
abstract = "To construct in situ velocity-porosity relationships for oceanic basalt, considering crack features, P- and S-wave velocity measurements on basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge were carried out under confining pressures up to 40 MPa. Assuming that the changes in velocities with confining pressures are originated by micro-crack closure, we estimated micro-crack aspect ratio spectra using the Kuster-Toks{\"o}z theory. The result demonstrates that the normalised aspect ratio spectra of the different samples have similar characteristics. From the normalised aspect ratio spectrum, we then constructed theoretical velocity-porosity relationships by calculating an aspect ratio spectrum for each porosity. In addition, by considering micro-crack closure due to confining pressure, a velocity-porosity relationship as a function of confining pressure could be obtained. The theoretical relationships that take into account the aspect ratio spectra are consistent with the observed relationships for over 100 discrete samples measured at atmospheric pressure, and the commonly observed pressure dependent relationships for a wide porosity range. The agreement between the laboratory-derived data and theoretically estimated values demonstrates that the velocity-porosity relationships of the basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge, and their pressure dependence, can be described by the crack features (i.e. normalised aspect ratio spectra) and crack closure.",
author = "Takeshi Tsuji and Iturrino, {Gerardo J.}",
year = "2008",
month = "10",
day = "1",
doi = "10.1071/EG08001",
language = "English",
volume = "39",
pages = "41--51",
journal = "Exploration Geophysics",
issn = "0071-3473",
publisher = "Consultants Bureau",
number = "1",

}

TY - JOUR

T1 - Velocity-porosity relationships in oceanic basalt from eastern flank of the Juan de Fuca Ridge

T2 - The effect of crack closure on seismic velocity

AU - Tsuji, Takeshi

AU - Iturrino, Gerardo J.

PY - 2008/10/1

Y1 - 2008/10/1

N2 - To construct in situ velocity-porosity relationships for oceanic basalt, considering crack features, P- and S-wave velocity measurements on basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge were carried out under confining pressures up to 40 MPa. Assuming that the changes in velocities with confining pressures are originated by micro-crack closure, we estimated micro-crack aspect ratio spectra using the Kuster-Toksöz theory. The result demonstrates that the normalised aspect ratio spectra of the different samples have similar characteristics. From the normalised aspect ratio spectrum, we then constructed theoretical velocity-porosity relationships by calculating an aspect ratio spectrum for each porosity. In addition, by considering micro-crack closure due to confining pressure, a velocity-porosity relationship as a function of confining pressure could be obtained. The theoretical relationships that take into account the aspect ratio spectra are consistent with the observed relationships for over 100 discrete samples measured at atmospheric pressure, and the commonly observed pressure dependent relationships for a wide porosity range. The agreement between the laboratory-derived data and theoretically estimated values demonstrates that the velocity-porosity relationships of the basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge, and their pressure dependence, can be described by the crack features (i.e. normalised aspect ratio spectra) and crack closure.

AB - To construct in situ velocity-porosity relationships for oceanic basalt, considering crack features, P- and S-wave velocity measurements on basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge were carried out under confining pressures up to 40 MPa. Assuming that the changes in velocities with confining pressures are originated by micro-crack closure, we estimated micro-crack aspect ratio spectra using the Kuster-Toksöz theory. The result demonstrates that the normalised aspect ratio spectra of the different samples have similar characteristics. From the normalised aspect ratio spectrum, we then constructed theoretical velocity-porosity relationships by calculating an aspect ratio spectrum for each porosity. In addition, by considering micro-crack closure due to confining pressure, a velocity-porosity relationship as a function of confining pressure could be obtained. The theoretical relationships that take into account the aspect ratio spectra are consistent with the observed relationships for over 100 discrete samples measured at atmospheric pressure, and the commonly observed pressure dependent relationships for a wide porosity range. The agreement between the laboratory-derived data and theoretically estimated values demonstrates that the velocity-porosity relationships of the basaltic samples obtained from the eastern flank of the Juan de Fuca Ridge, and their pressure dependence, can be described by the crack features (i.e. normalised aspect ratio spectra) and crack closure.

UR - http://www.scopus.com/inward/record.url?scp=52649176724&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=52649176724&partnerID=8YFLogxK

U2 - 10.1071/EG08001

DO - 10.1071/EG08001

M3 - Article

AN - SCOPUS:52649176724

VL - 39

SP - 41

EP - 51

JO - Exploration Geophysics

JF - Exploration Geophysics

SN - 0071-3473

IS - 1

ER -