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2004
Chaytor, J., C. Goldfinger, R.P. Dziak, C.G. Fox, Active deformation
of the Gorda "Plate": Constraining deformation models
with new geophysical data, Geology, in press 2004.
Davis, E., K. Becker, R. Dziak, J. Cassidy,
K. Wang, and M. Lilley, A Seafloor Spreading Episode on the
Juan de Fuca Ridge: Evidence for a Co-seismic crustal dilatation
and hydrothermal "anti-plume", Nature, in review,
2004
Dziak, R.P., D. R. Bohnenstiehl, H. Matsumoto,
C. G. Fox, D. K. Smith, M. Tolstoy, T-K Lau, J. H. Haxel,
M. J. Fowler, P- and T-wave detection thresholds, Pn velocity
estimate, and detection of lower mantle and core P-waves on
ocean sound-channel hydrophones at the mid-Atlantic Ridge,
Bull. Seism. Soc. Am., in press 2004.
Dziak, R.P., D. Smith, D. Bohnenstiehl, C.
Fox, D. Desbruyeres, H. Matsumoto, M. Tolstoy, and D. Fornari,
Evidence of a recent magma dike intrusion at the slow-spreading
Lucky Strike segment, Mid-Atlantic Ridge, J. Geophys. Res.,
in review, 2004.
Dziak,
R., J. Goslin, D. Smith, N. Lourenço, D. Bohnenstiehl,
H. Matsumoto, C. Fox, M. Tolstoy, J. Luis, Long-term Monitoring
of Northern Mid-Atlantic Ridge Earthquake Activity Using Autonomous
Hydrophone Arrays, Proceedngs from the RIDGE 2000 Workshop
on the Mid-Atlanitc Ridge, March 1-3, 2004.
Graeber,
F. M., Piserchia, P.-F. (2004) T-phase excitation in the NE
Indian Ocean mapped using variations in backazimuth over time
obtained from Multi-Channel Correlation of IMS hydrophone
triplet data, Geophysical J. International, 158, 239-256.
Smith,
D.K., R.P. Dziak, H. Matsumoto, C.G. Fox, and M. Tolstoy,
Autonomous Hydrophone Array Monitors Seismic Activity at Northern
Mid-Atlantic Ridge, Eos Transactions, AGU, 85, No 1., 1-5,
2004.
2003
Bohnenstiehl, D.R. M. Tolstoy, D.K. Smith, C.G. Fox and R.P.
Dziak, Time clustering behavior of earthquakes along the Mid-Atlantic
Ridge 15°-35°N: Observations from hydroacoustic monitoring,
Phys. Earth and Planet. Int., 138, No 2, 147-161, 2003.
Bohnenstiehl, D.R. and M. Tolstoy, Comparison
of teleseismic- and hydroacoustic-derived earthquake locations
along the north-central Mid-Atlantic Ridge and equatorial
East-Pacific Rise, Seismol. Res. Lett., 74, 791-802, 2003.
Cowen, J., E. T. Baker, R.P. Dziak, and M.
Lilley, Time-Critical Studies: Rapid response to Transient
Dynamic Mid-Ocean Ridge Events (abstract), Eos Transactions,
American Geophysical Union, Fall Meeting, 2003.
Dziak, R.P., W. W. Chadwick, Jr., C. G. Fox,
and R. W. Embley, Hydrothermal temperature changes at the
southern Juan de Fuca Ridge associated with a Mw 6.2 Blanco
Transform earthquake. Geology, v. 31, no. 2, p. 119-122, 2003.
Dziak, R., M. Park, H. Matsumoto, C. Fox,
S.-K. Byun, M. Fowler, J. Haxel, and R. Embley, Hydroacoustic
Records of the First Historical Eruption of Anatahan Volcano,
Mariana Islands (abstract), Eos Transactions AGU, Fall Meeting,
2004.
Goslin, J, N. lourenco, R.P. Dziak, D. Bohnenstiehl,
J. Haxel, Long-term Seismicity of the Reykjanes Ridge (North
Atlantic) Recorded by a Regional Hydrophone Array (abstract),
European Union of Geosciences, Sprint Meeting, Nice, France,
2004.
Okal, E.A., P-J. Alasset, O. Hyvernaud, and
F. Schindele, The Deficient T waves of Tsunami Earthquakes,
Geopys. J. Int., 152, 416-432, 2003.
Okal, E.A., T waves from the 1998 Papua New
Guinea Earthquake and Its Aftershocks: Timing the Tsunamigenic
Slump, Pure and Appl. Geophys., 160, 1843-1863, 2003.
Park, M. , R. Dziak , S.-K. Byun , and C.
Fox, and H. Matsumoto, Numerical Modeling of Sound from the
Eruption of Anatahan Volcano, Mariana Islands (abstract),
Eos Transactions AGU, Fall Meeting, 2004.
Reymond, D., O. Hyvernaud, J. Talandier, E.A.
Okal, T-wave Detection of Two Underwater Explosions off Hawaii
on 13 April 2000, Bull. Seism. Soc. Am., 93, No. 2, 804-816,
2003.
Smith, D.K., J. Escartin, M. Cannat, M. Tolstoy,
C.G. Fox, D. R. Bohnenstiehl, S. Bazin, Spatial and temporal
distribution of seismicity along the northern Mid-Atlantic
Ridge (15-35°N), J. Geophys. Res., 108, 2167, 10.1029/2002JB001964,
2003.
Talandier, J., and E.A. Okal, Hydroacoustic
signals from presumed CHASE explosions off Vancouver Island
in 1969-70: A modern perspective, Seismol. Res. Letts., in
press, 2003.
Yang, Y and D.W. Forsyth, Improving epicentral
and magnitude estimation of earthquakes from T-phases by considering
the excitation function, Bull Seism.Soc. Am., 93, 5, 2106-2122,
2003.
2002
Bohnenstiehl, D.R., M. Tolstoy, R.P. Dziak, C.G. Fox, and
D.K. Smith, Aftershocks in the mid-ocean ridge environment:
An analysis using hydroacoustic data, Tectonophysics 354,
49-70, 2002.
Butler, R. and C. Lomnitz, Coupled Seismoacoustic
Modes on the Seafloor, Geophys. Res. Lett, 29, No 10, 10.1029/2002GL014722,
2002
Dziak, R.P. and C.G. Fox, Evidence for Harmonic
tremor detected Across the Pacific Ocean Basin, J. Geophys.Res.,
vol. 29, no. 12, 10.1029/2001GL01391, 2002.
Pulli, J. J., and Z. M. Upton, Hydroacoustic
Observations of Indian Earthquake Provide New Data on T-waves,
Eos Transactions, Am. Geophys. Un., 83, No. 13, 2002.
Smith, D. K., M. Tolstoy, C. G. Fox, D. R.
Bohnenstiehl, H. Matsumoto, and M. J. Fowler, Hydroacoustic
monitoring of seismicity at the slow-spreading Mid-Atlantic
Ridge. Geophys,Res. Lett., 29, no.12, 10.1029/2001GL01391,
2002.
Talandier, J., O. Hyvernaud, E.A. Okal, and
P.-F. Piserchia, Long-range detection of hydroacoustic signals
from large icebergs in the Ross Sea, Antarctica, Earth Planet.
Sci. Letts., 203, 519-534, 2002.
2001
Caplan -Auerbach, J., C.G. Fox, F.K. Duennebier, Hydroacoustic
Detection of Submarine Landslides on Kilauea Volcano, Geophys.
Res., Lett., 28, No. 9, 1811-1813, 2001.
Dziak, R.P., Empirical Relationship of T-wave
Energy and Fault Parameters of Northeast Pacific Ocean Earthquakes,
Geophys. Res. Lett., 28, 2537-2540, 2001.
Fox, C.G., H. Matsumoto, and T.K.A. Lau, Monitoring
Pacific Ocean seismicity from an autonomous hydrophone array,
J. Geophys. Res., 106, 4183-4206, 2001.
Johnson,
H.P., R.P. Dziak, C.R. Fisher, C.G. Fox, and M.J. Pruis, Earthquakes
Influence Distant Hydrothermal Vents: The Far-field Effect
and Delayed Response, Eos Transactions AGU, 82, 233-236, 2001
Okal, E.A, T-phase Stations for the International Monitoring
System of the Comprehensive Nuclear-Test Ban Treay: A Global
Perspective, Seism. Res. Lett., 72, No. 2, 186-196, 2001.
Sohn, R.A. and J.A Hildebrand, Hydroacoustic
earthquake detection in the Arctic Basin with the Spinnaker
Array, Bull Seism. Soc. Am., 572-579, 2001.
2000
Dziak,
R.P., C.G. Fox, R.W. Embley, J.L. Nabelek, J. Braunmiller,
and R.A. Koski. Recent Tectonics of the Blanco Ridge, Eastern
Blanco Transform Fault Zone, Mar. Geophys. Res., 21 (5), 423-450,2000.
Johnson,
H.P., M.A. Hutnak, R.P. Dziak, C.G. Fox, I. Urcuyo, C. Fisher,
J.P. Cowen, J. Nabelek, Earthquake-Induced Changes in a Hydrothermal
System at the Endeavour Segment, Juan de Fuca Ridge, Nature,
407, 174-177, 2000.
Orcutt,
J., E. Bernard, C.-S. Chiu, C. Collins, C. deGroot-Hedlin,
R. Dziak, C. Fox, W. Hodgkiss, W.Kuperman, J. Mercer, W. Munk,
R. Odom, M. Park, D. Soukup, R. Spindel, F. Vernon, and P.
Worcester, Long-term observations in acoustics the Ocean Acoustic
Observatory Federation. Oceanography, 13(2), 57-63, 2000.
1999
Dziak, RP
and C.G. Fox, Long-term seismicity and ground deformation
at Axial Volcano, Juan de Fuca Ridge, Geophys Res. Lett.,
v:26, 3641-3644, 1999.
Dziak, RP
and C.G. Fox, The January 1998 earthquake swarm at Axial Volcano,
Juan de Fuca Ridge: Hydroacoustic evidence of a seafloor volcanic
activity, Geophys Res. Lett., v:26, 3429-3432, 1999.
Dziak, RP,
C.G. Fox, S.R. Hammond, T-K Lau, H. Matsumoto, A.E. Schreiner,
Real-Time detection of earthquake swarms using the SOSUS hydrophone
array: Hydroacoustic evidence of dike injections and seafloor
eruptions, Proceedings: Juan de Fuca Ridge Results Symposium:
A Retrospective., Seattle, WA, November 7-9, 1999.
Dziak, RP
and C.G. Fox, New insights into the seismotectonics of NE
Pacific ocean spreading centers, transform faults, and microplates
from hydroacoustic monitoring, IUGG/IASPEI., Symposium
on Seismotectonics, Birmingham, UK, July, 1999.
Fox, C.G.
and RP Dziak, Internal deformation of the Gorda Plate using
hydroacoustic monitoring methods. J. Geophys. Res.,
v:104, 17603-17615, 1999.
Fox,C.G.
and RP Dziak, Long-term monitoring of oceanic seismicity using
underwater acoustic techniques, IUGG/IASPEI., Symposium
on Seismotectonics, Birmingham, UK, July, 1999.
Slack, P.D.,
C.G. Fox, and RP Dziak. P wave detection thresholds, Pn velocity
estimates, and T-wave location uncertainty from oceanic hydrophones.
J. Geophys. Res., 104: 13061-13072, 1999.
1998
de Groot–Hedlin,
C.D., and J. Orcutt. Synthesis of earthquake generated T-waves, Geophys.
Res.; ett., n v:26, 1227-1230, 1998.
Dziak, RP
and C.G. Fox, Hydroacoustic Detection of Submarine Volcanic
Activity at Axial Volcano, Juan de Fuca Ridge, January 1998,
Eos Transactions, American Geophysical Union, San Francisco,
CA, v:79, No. 46, November 12, 1998.
Fowler, M.J.,
RP Dziak, and C.G. Fox, Improved Hydroacoustic Locations of
Northeast Pacific Ocean Earthquakes derived from Military
Hydrophone Arrays, Eos Transactions, American Geophysical
Union, San Francisco, CA, v:79, No. 46, November 12, 1998.
Fox, C.G.
and R.P. Dziak Hydroacoustic Detection of Volcanic Activity
on the Gorda Ridge, February - March 1996, Deep Sea Res.
II, 45: 2513-2530, 1998.
Description
of seismicity associated with a seafloor eruption and dike injection
along the northern Gorda Ridge. A total of 4093 earthquakes were detected
over a 3 week period on the U.S. Navy’s SOSUS hydrophones. The earthquakes
migrated a distance of 35 km over a 24 hr period (speed of ~ 0.55 m/s),
likely following the propagation of dike through the shallow oceanic
crust.
Fox, C.G.
and RP Dziak, Hydroacoustic Monitoring of Deep Ocean Earthquakes
Using the SOSUS Hydrophone Arrays, , Eos Transactions,
American Geophysical Union, San Francisco, CA, v:79, No. 46,
November 12, 1998
Hanson, J.A.,
and H.K Given. Accurate azimuth estimates from a large aperture hydrophone
array using T-phase waveforms. Geophys. Res. Lett., 25:365-368,
1998
Okal, E.A.,
and J. Talandier. Correction to T waves from the Great 1994 Bolivian Deep
Earthquake in Relation to Channeling of S wave Energy up the Slab. J.
Geophys. Res., 103, 2793-2794, 1998.
Talandier,
J., and E.A. Okal. On the mechanism of conversion of seismic waves to
and from T-waves in the vicinity of island shores. Bull Seism. Soc.
Am., 88, 621, 1998.
This paper
considers the conversion of seismic waves to and from T-waves
in the vicinity of islands. They found that the steep island slopes
play a pivotal role in allowing efficient conversion between P-waves
in the island structure and T-waves in the water column.
1997
Blackman,
D.K., And JA Orcutt. Seismoacoustic Recordings of a Volcanic
Event on the Mohns Ridge. J. Acoust. Soc. Am.(abstract),
105, 3069, 1997.
Dziak,
RP, C.G. Fox, H. Matsumoto, and AE Schreiner. The 1992 Cape
Mendocino Earthquake Sequence: Seismo-Acoustic Analysis Using
Fixed Hydrophone Arrays. Mar. Geophys. Res., v:19,
137-162, 1997.
Dziak, RP
and C.G. Fox. Long-Term Seismicity and Ground Deformation
at Axial Volcano, Juan de Fuca Ridge. Eos Transactions,
American Geophysical Union, San Francisco, CA, v:78, No. 46,
November, 1997.
Fox, C.G.
and RP Dziak. Hydroacoustic Monitoring of Magmatic Activity
on the Mid-Ocean Ridge. Eos Transactions, American
Geophysical Union, San Francisco, CA, v:78, No. 46, November,
1997.
Fox, C.G.
Hydroacoustic Monitoring of the Distribution of Magmatic Activity on the
Mid-Ocean Ridge. European Geophysical Society, Vienna, Austria,
April, 1997.
Hanson, JA,
and H.K. Given. Performance of an Island Seismic Station for
Observing Hydroacoustic T-phases. Eos Transactions
(abstract), American Geophysical Union, San Francisco, CA,
v:78, No. 46, November, 1997.
Hanson, JA,
and H.K. Given. Locating ridge seismicity near Ascension Island
using hydroacoustic and seismic data, J. Acoustic Soc.
Am.(abstract), 105, 3070, 1997.
McLaughlin.
T-phase Observations at San Nicolas Island, California. Seism. Res.
Lett. (abstract), v:68, 296, 1997.
Okal, E.A.,
And J. Talandier. T waves from the Great 1994 Bolivian Deep
Earthquake in Relation to Channeling of S wave Energy up the
Slab, J. Geophys Res., 102, 27421-27437, 1997.
Pasyanos,
M. E., and B. Romanowicz. Observations of T-phases Across Northern California
Using the Berkeley Digital Seismic Network. Eos Transactions (abstract),
American Geophysical Union, San Francisco, CA, v:78, No. 46, November,
1997.
Piserchia,
P-F, J. Virieux, D. Rodrigues, S. Gaffet, and J. Talandier. A Hybrid Numerical
Model of T-wave propagation: Application to the Mid-plate Experiment.
Geophys. J. Int., 1997
1996
Chapman,
N.R. and R. Marrett. Acoustic T-phase Directionality Measurements Using
a Towed Line Array. J. Acoust. Soc Am. (abstract), v:100,
No.4, 2641, 1996.
Duennebier,
F.K., And C.N. McCreery The Earthquake T phase: MILS Hydrophone
Array Results. J. Acoust. Soc Am. (abstract), v:100,
No.4, 2638, 1996.
deGroot-Hedlin,
C., and J. Orcutt. Observations of Hydro-acoustic Phases from Submarine
Earthquakes in the Pacific. Eos Transactions (abstract), American
Geophysical Union, San Francisco, CA, v:61, No.43, November, 1996.
Dysart, P.S.,
H.W. Laney, and R. Willemann. Hydroacoustic Event Detection and Classification
at Point Sur and Wake Island. Eos Transactions (abstract), American
Geophysical Union, San Francisco, CA, v:61, No.43, November, 1996.
Dziak,
RP, C.G. Fox, R.W. Embley, J.E. Lupton, G.C. Johnson, W.W.
Chadwick, and R.A. Koski. Detection of and Response to a Probable
Volcanogenic T-wave Event Swarm on the Western Blanco Transform
Fault Zone. Geophys Res. Lett., v:23, No. 8, 873-876,
1996.
Dziak, RP,
C.G. Fox, and P.D.Slack. T-wave Source Level and Earthquake
Fault Parameters: Empirically Derived Scaling Relationships.
J. Acoust. Soc Am. (abstract), v:100, No.4,
2639, 1996.
Dziak,
RP and C.G. Fox. Seismoacoustic Analysis of Tectonic Activity
Along Northeast Pacific Ocean Transform Faults. European
Seismological Commission, XXV General Assembly (abstract),
Reykjavik, Iceland, September, 1996.
Fox, C.G.
and RP Dziak. Monitoring Volcanism on the Mid-Ocean Ridge
Using Hydroacoustic Techniques. European Seismological
Commission, XXV General Assembly (abstract), Reykjavik,
Iceland, September, 1996.
Fox, C.G.,
and RP Dziak. Monitoring Microseismicity in the Northeast
Pacific Using Hydroacoustic Techniques. J. Acoust.
Soc Am. (abstract), v:100, No.4, 2638, 1996.
Hanson, JA,
H.K. Given, and J. Berger. Earthquake activity near Ascension
Island, south Atlantic Ocean, as seen by a combined seismic/hydrophone
array, Geothermics, 25: 507-519, 1996.
Harris, B.H.,
And T.F. Hauk. Acoustic Array Observation of Seismic Events.
J. Acoust. Soc Am. (abstract), v:100, No.4,
2640, 1996.
Hildebrand,
JA, C.G. Fox, and RP Dziak. A Multipath Model for T-wave Generation
of Seafloor Earthquakes. J. Acoust. Soc Am.
(abstract), v:100, No.4, 2639, 1996.
Keenan, R.E.
Arctic Abyssal T-phase Coupling to the Ocean Acoustic Channel. J.
Acoust. Soc Am. (abstract), v:100, No.4, 2640, 1996.
Laney, H.W.,
P. Dysart, H. Freese, and R.J. Willemann. An Automated System for Detecting
and Classifying In-Water Explosions and T-phases. J .Acoust.
Soc Am. (abstract), v:100, No.4, 2641, 1996.
Lysanov,
Y.P. Trapping of Hydroacoustic Waves Generated by Underwater Earthquakes
Into a Sound Channel. J. Acoust. Soc Am. (abstract), v:100,
No.4, 2641, 1996.
Okal, E.A.,
And J. Talandier. T-wave Detection of Underwater Volcanism
by Land-based Seismic Stations: The Example of the Hollister
Ridge. J. Acoust. Soc Am. (abstract), v:100,
No.4, 2640, 1996.
Schmidt,
H. and J.T. Goh. Modeling Oceanic T-phase Generation Using Coupled Wave-Number-Integration
Approaches. J. Acoust. Soc Am. (abstract), v:100, No.4,
2641, 1996.
Sperry, B.,
J.T. Goh, and H. Schmidt. Possible Mechanisms for T-phase Generation.
J. Acoust. Soc Am. (abstract), v:100, No.4, 2641, 1996.
Talandier,
J., and E.A. Okal. T waves from underwater volcanoes in the Pacific Ocean:
Ringing witnesses to geyser processes?, Bull. Seism. Soc. Am.,
86, 1529-1544, 1996
1995
Fox,
C.G., W.E. Radford, RP Dziak, T-K Lau, H. Matsumoto, and AE
Schreiner. Acoustic Detection of a Seafloor Spreading Episode
on the Juan de Fuca Ridge Using Military Hydrophone Arrays.
Geophys Res. Lett., v:22, No. 2, 131-134, 1995.
Dziak,
RP, C.G. Fox, and AE Schreiner. The June-July 1993 Seismoacoustic
Event at CoAxial Segment, Juan de Fuca Ridge: Evidence for
a Lateral Dike Injection. Geophys Res. Lett., v:22,
No. 2, 135-138, 1995.
Dziak, RP
and C.G. Fox. Juan de Fuca Ridge T-wave Earthquakes August
1991 to Present: Volcanic and Tectonic Implications. Eos
Transactions (abstract), American Geophysical Union, San
Francisco, CA, v:76, No. 43, October 1995.
Kong, L.S.L.,
Dziak, RP, and C.G. Fox. Detection and Location of Hawaiian
Earthquakes Using NE Pacific Military Hydrophone Arrays. Eos
Transactions (abstract), American Geophysical Union, San
Francisco, CA, v:76, N0.43, October, 1995
Koyanagi,
S., K. Aki, N. Biswas, and K. Mayeda. Inferred Attenuation
from Site Effect-Corrected T phases recorded on the Island
Of Hawaii’i. Pure Appl. Geophys., v:144, 1-17, 1995.
Schreiner,
AE, C.G. Fox, and RP Dziak. Spectra and Magnitudes of T-waves
from the 1993 Earthquake Swarm on the Juan de Fuca Ridge.
Geophys Res. Lett., v:22, No. 2, 139-142, 1995.
1994
Fox,
C.G., RP Dziak, H. Matsumoto, and AE Schreiner. Potential
for Monitoring Low-level Seismicity on the Juan de Fuca Ridge
Using Fixed Hydrophone Arrays. Mar. Tech. Soc., v:27,
No. 4, 22-30, 1994.
Fox, C.G.
and SR Hammond. The VENTS Program T-phase Project and NOAA’s
Role in Ocean Environmental Research. Mar. Tech. Soc.,
v:27, No.4, 70-74, 1994.
Nishimura,
CE and D.M. Conlon. IUSS Dual Use: Monitoring Whales and Earthquakes
Using SOSUS. Mar Tech. Soc., v:27, No.4, 13-21, 1994.
Schreiner,
AE and C.G. Fox. Comparisons of Ridge Crest Earthquake Waveforms
Recorded on SOSUS Hydrophones with Ocean Bottom Seismometers
in the Near-Field. J. Acous. Soc. Am.(abstract), v:95,
No. 5, May, 1994.
1993
Fox,
C.G. , SR Hammond, and E.N. Bernard. Monitoring the Juan de
Fuca Ridge Using US Navy Fixed Hydrophone Arrays. The Ocean
Society (abstract), Seattle, WA, April, 1993.
1992
Hiyoshi,
Y., Walker, D.A., and C.S. McCreery, T-phase Data and Regional Tsunamigenesis
in Japan, Bull Seism. Soc. Am., 54, 2085-2086.
1991
Hammond,
SR, and DA Walker, Ridge event detection: T-phase signals
from the Juan de Fuca spreading center, Mar. Geophys. Res.,
v:13, 331-348, 1991.
Using
data from MILS, ten times more earthquakes were recorded on ocean hydrophones
than were reported by the global seismic network during the mid-1960's.
Various radiators along the Juan de Fuca ridge are identified and are
correlated with geological phenomena.
Keenan,
R. E., and L.R.L. Merriam, Arctic abyssal T-phases: coupling seismic energy
to the ocean sound channel via under-ice scattering, J. Acoust. Soc.
Am., 89, 1128-1133, 1991.
Under-ice
scattering is proposed to explain the generation of abyssal T-phases
in the Arctic. It is also suggested that a similar mechanism (sea surface
scattering) can generate abyssal T-phases in the open oceans.
1989
McClelland,
L., T. Simkin, M. Summers, E. Nielsen, T.C. Stein, Global Volcanism
1975-1985, Prentice-Hall, Inc., 1989.
This
is a compilation of the Smithsonian Institution's Scientific Event Alert
Network (SEAN) reports on volcanic activity from the years 1975-1985.
Talandier,
J. Submarine volcanic activity: detection, monitoring, and interpretation,
EOS, Trans. Amer. Geophys. Un., 70, 561, 568-569, 1989.
1987
Smith, W.D.,
Underground nuclear explosions recorded at Raratonga examination of mb
from T-phase amplitude, Geophys. J. R. astr. Soc., 90, 35-42,
1987
Talandier,
J., and E.A. Okal, Seismic detection of underwater volcanism: the example
of French Polynesia, Pure Appl. Geophys., 125, 919-950,
1987.
This
is a comprehensive review on detecting underwater volcanism using seismometers
in French Polynesia with numerous references to past work in other areas.
A strong argument is made based on seismic observations that only shallow
volcanic events produce T-phases.
1986
Kadykov,
I.F., Acoustics of Underwater earthquakes, Nauka, Moscow, 1986
(in Russian).
I
have seen this book, but it certainly has the most interesting title.
The author's name may be Kadydov.
Okal,
E.A., And J. Talandier, T-wave duration, magnitudes and seismic
moment of an earthquake: application to tsunami warning, J.
Phys. Earth, 34, 19-42, 1986.
A
theoretical model based primarily on empirical seismological relationships
is presented which attempts to correlate T-phase duration and seismic
moment. This simple model is then tested using a data set collected
at Tahiti.
1985
Cansi, Y.,
and N. Bethoux, T waves with long inland paths: synthetic seismograms,
J. Geophys. Res., 90, 5459-5465, 1985.
Synthetic
seismograms where the coupling of T- to P-phase is based on diffraction
theory are generated and compared to observed T-phases. The basic conclusion
reached is that the shape of the continental slope where the conversion
takes place, plays a major role in the amplitude and duration of recorded
T-phases.
Hall,
L.H., Rumble IV seamount -- no rumble?, New Zealand J. Geol. Geophys.,
28, 569, 1985.
A
very short note pointing out that acoustic noise from Kibblewhite's
Rumble IV seamount was probably from Rumble III. Furthermore, the apparent
signal from Rumble III was probably shipping noise. Apparently the array
geometry had been altered.
Hamada,
N., T waves recorded by ocean bottom seismographs off the south coast
of Tokai area, Central Honshu, Japan, J. Phys. Res., 33,
391-410, 1985.
This
is a good paper which presents T-phase data recorded on permanent three-component
OBS's. Because the receivers are geophones rather than hydrophones (i.e.
wave polarization), and because the receivers are located off-shore
(hence minimizing the contamination of the T-phase by propagation along
a continental path), the authors are able to rigorously test past hypotheses
about T-phases. One of their observations is that the particle motion
for the T-phases is prograde elliptic in the vertical radial plane regardless
if the receiver is above or below the axis of the SOFAR channel this
represents motion of the lower boundary (sediment column) rather than
motion of the water. A path dependency of the amplitudes is also shown
(i.e. shallow water depths paths have smaller amplitudes). They are
also puzzled about why T-phases should be dispersive.
Sereno,
T., and J. Orcutt, Synthesis of realistic oceanic Pn wave trains, J.
Geophys. Res., 90, 12755-12776, 1985.
While
this paper is primarily about generating synthetic Pn wave trains, it
does have a short section about the generation of abyssal T phases.
The authors propose that abyssal T phases are water as well as crustal
reverberations generated by postcritical P wave reflections off the
Moho.
Walker,
DA, and CS McCreery, Significant unreported earthquakes in
"aseismic" regions of the western Pacific, Geophys. Res.
Lett., 12, 433-436, 1985.
Po,
So, and T-phases are used to identify various unreported
earthquakes in the western Pacific. One rather anomalous
unreported event produced large PO/So phases the estimated
magnitude of this event is m = 5 to 6. Once again, the need
for oceanic seismic/hydrophone stations is presented.
Walker,
DA, CS McCreery, and F.J. Oliveira, Kaitoku Seamount and the
mystery cloud of 9 April 1984, Science, 227,
607-611, 1985.
A
month long earthquake swarm related to a shallow underwater volcanic
eruption of Kaitoku Seamount, is recorded on the Wake Island hydrophone
array (and also in Tahiti). Numerous T-phases are recorded. But what
about the mystery cloud seen miles and miles away? Is it related to
Kaitoku or is it the results of unknown evil forces?
1984
Hall, L.H.,
A recent calendar of activity from Rumble III together with some related
thoughts, Defence Scientific Establishment Technical Note 84/1,
1984.
I
do not have this technical report which apparently has a major bearing
on the results obtained by Kibblewhite (1966, 1967). Hall refers to
this report in his 1985 short note.
Kadydov,
I.F., Computation of underwater acoustic signals from an earthquake with
due allowance for the ocean floor topography, Volc. Seism., 5, 207-212,
1984. (Translated from Vulkanol. i Seismol.)
Keenan,
RE, and I. Dyer, Noise from Arctic Ocean earthquakes, J.
Acoust. Soc. Am., 75, 819-825,1984.
T-phases
recorded from a horizontal array of hydrophones deployed during the
FRAM II experiment are hypothesized to have originated from earthquakes
along the mid-Arctic ridge. The proposed mechanism for the generation
of T is the scattering of acoustic signals from the base of the ice
cover. The long duration of the observed T-phase is somewhat difficult
to explain.
Talandier,
J., and E.A. Okal, New surveys of Macdonald seamount, southcentral Pacific,
following volcanoseismic activity, 1977-1983, Geophys. Res. Lett.,
1, 813-816, 1984.
During
1977-1983, twelve seismic swarms at Macdonald seamount are detected
by the French Polynesia seismic network using T-phases. The nature of
the events indicate shallow volcanic activity. A bathymetric survey
of Macdonald in 1982 indicates that the summit is shallower than when
first surveyed by Johnson (1970).
1983
Brocher,
T.M., T-phases from an earthquake swarm on the Mid-Atlantic Ridge at 31.6°N,
Mar. Geophys. Res., 6, 39-49, 1983.
T-phases
from the Mid-Atlantic Ridge (31.6°N) are recorded on an OBS array deployed
off Nova Scotia. The T-phase activity spanned a total of 30 hours in which
16 events were detected. Two of the events were located by the world-wide
seismic network. Using the duration of the T-phase as a measure of the
magnitude of the event, a b value of 1.2 is estimated for the swarm. A
suggestion is made that ocean sensors might work better than the worldwide
seismic network in detecting activity along mid-ocean ridges.
Ghalib,
H.A.A., M. Barazangi, and B.I. Isacks, Excitation of T phases from shallow
and intermediate-depth earthquakes in the southern Vanuatu (New Hebrides)
Arc, Bull. Seism. Soc. Amer., 73, 1921-1928, 1983.
Ivashchenko,
A.I., F.D. Zhuk, AI Spirin, R.R. Kharvi, and S.L. Pul, T-phases
recorded by ocean-bottom seismographs near the junction of
the Kuril and Japan Trenches, Seismological Studies of the
World Ocean, ed. S.M. Zverev and S.A. Boldyrev, 87-93, 1983
(in Russian).
1982
Talandier,
J., and E. Okal, Crises sismiques du volcan Mac-Donald (Ocean Pacifique
Sud), C.R. Acad. Sc. Paris, Serie II, 295,
195-200, 1982 (in French).
Sigh,
another article written in French. This paper is about the seismicity
of Macdonald Seamount during 1967-1981. Some of the results are presented
in Talandier and Okal, 1984.
Walker,
DA, Oceanic Pn/Sn phases: a qualitative explanation and reinterpretation
of the T-phase, Hawaii Institute of Geophysics Report,
HIG-82-6, 18 pp., 1982.
This
paper proposes that abyssal T phases are generated by the
coupling of Pn and Sn energy into the SOFAR channel. Note
that in later references by Walker, Pn and Sn are renamed,
PO and So.
1981
Cansi, Y.,
Etude experimentale des ondes T, these de 3eme cycle, Univ. Paris
XI, Orsay, 1981 (in French).
Once
again I cannot read French, nor do I have a copy of this thesis. I assume
that part of this thesis is presented in Cansi and Bethoux (1985).
Kadykov,
I.F., Yu. S. Belavin, and U Ton II, T-phase radiation of earthquake signals
by submarine flanks of the Kuril Islands, Vulkanol i Seismol., No. 4,
102-105, 1981 (in Russian).
I
do not have this paper (which was referenced by Kadydov, 1984) as this
journal was not translated into English at that time. This paper is
apparently about T-phases observed in the Sea of Okhotsk. Note that
the authors last name is spelled Kadykov in Russian, as oppose to Kadydov
when translated into English.
Shapira,
A., T phases from underwater explosions off the coast of Israel, Bull.
Seism. Soc. Am., 71, 1049-1059, 1981.
T
phases from underwater explosions are recorded on three land-base seismographs.
Calculations are made on the quality factor Q, travel-time, and duration.
1980
Katsumata,
M., and K. Tokunaga, On the T-waves observed at Minamidaito-jima, Okinawa,
Pap. Meteorol. Geophys., 31, 191-204, 1980 (in Japanese)
I
do not have a copy of this paper nor can I read Japanese.
Okal,
E.A., J. Talandier, K.A. Sverdrup, and T.H. Jordan, Seismicity and tectonic
stress in the southcentral Pacific, J. Geophys. Res., 85,
6479-6495, 1980.
Most
of this study is about what is stated in the title. This paper is included
in the list because there is one short section on T-phases.
Solov'yev,
SL, Y.S. Belavin, I.F. Kadykov, and U. Ton Il, T-phase recording
in earthquake signals of the northwestern Pacific Ocean, Vulkanol.
Seismol., 1, 60-69, 1980 (in Russian).
1979
Adams, R.D.,
T-phase recordings at Raratonga from underground nuclear explosions, Geophys.
J. R. astr. Soc., 58, 361-369, 1979.
T-phases
from presumed underground nuclear detonations in French Polynesia are
found to have generated large amplitude T-phases recorded at Raratonga.
An estimate of the magnitude and yield of the explosions is derived
using the duration of the signal, not the amplitude. Later arrivals
representing reflections off of near-by seamounts are also observed.
Talandier,
J., and E.A. Okal, Human perception of T waves: the June 22, 1977 Tonga
earthquake felt on Tahiti, Bull. Seism. Soc. Am., 69, 1475-1486,
1979.
As
previously demonstrated, the conversion of T to P-phases can result
in the perception of an apparent local earthquake. The path dependency
of this effect is also presented.
1978
Denham, R.N.,
R.W. Bannister, K.M. Guthrie, and D.G. Browning, Underwater acoustic signals
from a Kermadec Ridge earthquake, New Zealand J. Geol. Geophys., 21,
545-547, 1978.
P,
S, and T waves are recorded on a hydrophone in the Fiji Basin from a
Ms 6.9 earthquake in the Kermadec Trench (not the Ridge as stated in
the title). The hydrophone was at a depth of 900 m and was deployed
during an ambient noise experiment.
Walker,
DA, CS McCreery, G.H. Sutton, and F.K. Duennebier, Spectral
analyses of high-frequency Pn and Sn phases observed at great
distances in the western Pacific, Science, 199,
1333-1335, 1978.
The
quality factor, Q, for Pn and Sn (PO and So) in the Western
Pacific are computed assuming that the spectrum of the source
is given by the spectrum of observed T-phases. In some instances,
the computed Q is abnormally high which leads to the hypothesis
that the T-phase spectrum is somewhat attenuated.
1976
Johnson,
R.H., Possible submarine volcanic eruption off southern California, Deep
Sea Res., 23, 265-267, 1976.
100
explosions were recorded in a 40 min time span on hydrophones located
at Oahu, Midway, and Wake from a probable volcanic eruption off southern
California. The shallowest seamounts in the calculated source region
is on the order of 2000 m depth. However, the bathymetry is poorly constrained.
(Note: would be nice to check more recent bathymetric maps for this
region).
Talandier,
J., and G.T. Kuster, Seismicity and submarine volcanic activity in French
Polynesia, J. Geophys. Res., 81, 936-948, 1976.
Seismic
activity from numerous sites in the vicinity of French Polynesia is
monitored using a local array of seismometers several swarms resembling
volcanic activity The presence or absence of T-phases for many of the
events appears to depend on the propagation path (ie. obstacles). This
paper also speculates whether one would expect T-phases from deep underwater
volcanic events.
1975
Shimamura,
H., and T. Asada, T waves from deep earthquakes generated exactly at the
bottom of deep trenches, Earth Planet. Sci. Lett., 27, 137-142,
1975.
In
this paper, the authors propose that the T-phases that they observe
are not SOFAR propagated waves but are instead multiply reflected signals.
They do not mention possible normal-mode propagation.
1974
Galanopoulos,
A.G., And J.C. Drakopoulos, A T phase recorded on an accelerogram,
Bull. Seism. Soc. Am., 64, 717-719, 1974.
This
is the only published reference to a recording of T-phase on an accelerogram.
The earthquake source is relatively close to the receiving instrument
in Greece. The acceleration of the T-phase was only 0.02 g compared
to a peak of 0.54g.
Gibowicz,
S.J., J.H. Latter, and G.K. Sutton, Earthquake swarm associated with volcanic
eruption, Curacoa Reef area, Northern Tonga, July 1973, Ann. Geofis.,
27, 443-475, 1974.
This
paper reports on a major earthquake swarm associated with an underwater
volcanic eruption which occurred at Curacoa Reef. The character of the
swarm appears to be divided into three distinct phases as constrained
by changes in the computed b-values. T-phases were recorded on seismic
stations seaward from the Tonga trench it is hypothesized that the source
of the P to T conversion took place in the trench region. A compilation
of ML versus T-phase amplitude as recorded at Afimalu indicates that
the amplitude of the T-phase = 101.5ML
Northrop,
J., T-phases from the Hawaiian earthquake of April 26, 1973, J. Geophys.
Res., 79, 5478-, 1974.
T-phases
from the large (m = 6.2) Hawaiian earthquake produced T-phases that
were recorded on SOFAR hydrophones (MILS) at Wake, Midway, and Kaneohe.
An interesting point is that no P wave arrival was recorded at the more
distant stations. Also, reflections from several seamounts in the Gulf
of Alaska were also recorded this is unusual for earthquakes while more
common for explosive shots.
Northrop,
J., Detection of low-frequency underwater sounds from a submarine volcano
in the Western Pacific, J. Acoust. Soc. Am., 56, 837-841,
1974.
Data
collected by the Pacific Missile Impact Location System indicate persistent
acoustic activity from a region north of the Marianas Islands. It is
proposed that it is associated with a shallow charted seamount and that
the volcanic activity was explosive. Spectral banding observed for some
of the events.
1973
Johnson,
R.H., Acoustic observations of nonexplosive submarine volcanism, J.
Geophys. Res., 78, 6093-6096, 1973.
T-phases
which exhibit spectral banding are used to infer that a seamount in
the Marianas underwent a period of underwater volcanic activity. The
volcanism is assumed to be nonexplosive as no visual indication of such
an activity was observed in a populated island only 40 km away. There
is some discussion concerning the acoustic source of "quiescent" underwater
volcanism.
Northrop,
J., T-phase radiation from the Cannikin explosion, J. Geophys. Res.,
78, 1809-1817, 1973.
While
the source was not an earthquake, this reference is included because
it was an underground explosion (buried point source, initial coupling
to the ground). The receivers used in this study are the SOFAR MILS
hydrophones. The data show numerous precursors to the main T-phase which
represent radiation (P to T) from sites between the source and the receivers.
Numerous reflections from bathymetric features (e.g. seamounts) resulted
in reverberations two hours after the main T-phase. Finally, the onset
of the main T-phase was sharper than that from earthquakes in the Aleutians.
This
paper is included in the T-phase reference list because it deals with
the dispersion of acoustic waves in the SOFAR channel dispersion is also
observed for T-phases.
1972
Bath, M.,
and M. Shahidi, T-phases from Atlantic earthquakes, Pure Appl. Geophys.,
92, 74-114, 1972.
This
paper presents T-phase data from events primarily along
the Mohns and Knipovich Ridges. There are some interesting
results and conclusions reached. The primary one is that
T-phases propagated primarily via surface-bottom reflections
this is constrained by measured travel-times and by computed
dispersion curves. The duration of the T-phase is also analyzed.
Johnson,
R.H., And R.A. Norris, Significance of spectral banding in
hydroacoustic signals from submarine volcanic eruptions: Myojin
1970, J. Geophys. Res., 77, 4461-4469, 1972.
Spectral
analysis of T-phases from a confirmed volcanic event shows the presence
of correlated spectral peaks with time. These peaks are not at constant
frequency, but instead shift as a function of time. It is proposed that
the spectral banding represents multiple water reverberations with the
spectral banding caused by constructive interference of the reverberations.
Confirmation of volcanic activity is given by observations made by a
Japanese fishing boat of discoloration of the sea and also explosion
felt on the boat.
Northrop,
J. T-phases, in The Great Alaskan Earthquake of 1964: Oceanography
and Coastal Engineering, 19-24, 1972.
T
phases recorded on MILS from the 1964 Good Friday Alaskan earthquake
and aftershocks are presented. The main shock produced T phases that
lasted about 3 hours. The strongest T phases generated for the aftershocks
were produced by earthquakes with hypocenters below the upper part of
the continental slope (see Wadati and Inouye, 1955). This paper is a
nice summary of T-phases.
Talandier,
J. Etude et prevision Des tsunamis en Polynesie Francaise,
These d' Universite, Universite Pierre-et-Marie Curie, Paris,
128 pp., 1972 (in French).
I
cannot read an entire thesis written in French which is a mute point
as I do not have a copy of this. However, I believe that there are considerable
important points presented in the thesis.
Walker,
DA, G.P. Woollard, G.H. Sutton, and J.J. LeTourneau, Easter
Island seismograph observations indicative of sea-floor spreading,
plate-edge seismicity relationships, and prediction of earthquakes
along the west coast of the Western Hemisphere, Hawaii
Institute of Geophysics Report, HIG-72-2,
25 pp., 1972.
In
this technical report, some unusual data is reported which may be T-phases
from events along the EPR.
Zhuk,
FD, and SL Solov'yev, Possible recording of the hydroacoustic
waves generated by earthquakes in the Pacific Ocean by the
seismic stations of the USSR, in, Volny Tsunami
1971
Johnson,
R.H., R.A. Norris, F.K. Duennebier, and J. Northrop, T-phase data on Kamchatka/Kurils
earthquakes: a reply, Bull. Seism. Soc. Am., 61, 791-794,
1971, with a reply by J.F. Evernden, pg 795.
This
is your standard reply and counter-reply with both sides basically considering
themselves correct. The discussion essentially boils down to one of
the use and misuse of statistics.
Northrop,
J., and M.F. Morrison, Underwater sound signals from the Amchitka Island
underground and underwater explosions, J. Geophys. Res., 76,
1985-1992, 1971.
T-phase
data from a 1-MT underground explosion (Milrow), a 340 T underwater
detonation, and two earthquakes are analyzed. The results are used to
determine criteria for discriminating between the three types of sources.
In general, underground explosions and earthquakes are similar except
for differences in the spatial extent and depth (attenuation of higher
frequencies) of the source region. Differences between underwater and
underground explosions are due to differences between direct and indirect
(P to T conversion) coupling of the seismo/acoustic energy.
1970
Evernden,
J.F., T-phase data on Kamchatka/Kurils earthquakes, Bull. Seism. Soc.
Am., 60, 1061-1076, 1970.
This
paper is a critical analysis of the Duennebier and Johnson (1967), which
attempts to explain discrepancies between the source location and origin
time as computed by T-phase versus teleseismic data. The basic premise
is that there can be virtual sources for the T-phases which are the
result of focussing and defocussing of the acoustic energy due to the
shape of the P to T source region.
Johnson,
R.H., Estimating rupture length from T waves, in Tsunamis in the Pacific
Ocean, Proc. of the International Symposium on Tsunamis and Tsunami
Research, ed. W.M. Adams, 253-259, East-West Center Press, Honolulu,
1970.
The
problem of determining the fault length of large earthquakes is presented
along with a description of how an array of hydrophones at a single
site might be able accomplish this task. The role of multiple radiation
points as described by Johnson and Norris (1968) is also restated.
Johnson,
R.H., And R.A. Norris, T-wave generation mechanisms, Hawaii
Institute of Geophysics Report, HIG-70-7, 15
pp., 1970.
This
the final report of the T-phase working group at the Hawaii Institute
of Geophysics in which over 400 sonograms from T-phases located all
over the Pacific are presented. A review of past work performed by this
group is given with an emphasis placed on determining the mechanisms
by which T-phases are generated. In general, it is conjectured that
a varied combination of the contribution of differences in bottom-slope,
bottom roughness, and sound velocity variations.
Johnson,
R.H., Active submarine volcanism in the Austral Islands, Science,
167, 977, 1970.
Strictly
speaking, this should not be listed with the T-phase papers since it
about a bathymetric survey of Macdonald seamount. However, this is a
classic paper about how to do science on one's vacation with the wife
and kids, while still having lots of fun. In other words, get a sailing
boat, get a echo sounder, load up the family, sail to Macdonald seamount,
and do some science.
Norris,
R.A., And D.N. Hart, Confirmation of SOFAR hydrophone detection
of submarine eruptions, J. Geophys. Res., 75,
2144-2147, 1970.
T-phases
from location of one of the five hypothesized volcanic eruptions in
Norris and Johnson (1969), Farallon de Pajaros, is recorded on March
11 and 12, 1969 (the previous activity was in the spring of 1967). The
T-phases display the same impulsive onset, high frequencies, and spectral
banding of the 1967 event. By chance, in 1969, a Japanese tuna boat
was in the immediate vicinity and noted three explosions and discoloration
of the seawater which is highly indicative of a submarine volcanic eruption.
Northrop,
J., Accuracy of earthquake epicenters on the Gorda Ridge, Bull. Seism.
Soc. Am., 60, 265-267, 1970.
In
this short note, the discrepancy between epicentral locations of earthquakes
on (or near) the Gorda Ridge as calculated by T-phases versus P and
S-P travel times is explained. In the former case, the epicenters are
located on the ridge, while in the latter, they are located to the east
of the ridge. As it turns out, Northrop is correct in his assessment
that the body-wave locations are systematically incorrect due to azimuthally
biased station coverage (i.e. poor station coverage to the west).
1969
Auld, B.,
G. Latham, A. Nowroozi, and L. Seeber, Seismicity off the coast of Northern
California determined from ocean bottom seismic measurements, Bull.
Seism. Soc. Am., 59, 2001-2015, 1969.
In
this paper, a brief mention is made to the recording of T-phases on
an ocean bottom seismometer deployed in 4 km of water off San Francisco
from earthquakes along the Mendocino Fracture Zone to the north. One
comment is that the amplitude on the horizontal N-S component is larger
than that on the E-W component.
Norris,
R.A., And R.H. Johnson, Submarine volcanic eruptions recently
located in the Pacific by SOFAR hydrophones, J. Geophys.
Res., 74, 650-664, 1969.
T-phase
data from the Pacific Missile Range network are used to identify five
probable volcanic sources in the Pacific. The spatial distribution of
the acoustic sources ranges from one in the Austral seamounts (this
turns out to be Macdonald Seamount), two in the Marianas (Saipan and
Farallon de Pajaros), one in the Aleutians (near Amilia), and one in
Nanpo Shoto (Tori-shima). The primary discrimination tools which leads
to a volcanic origin hypothesis are the similarity with shallow nuclear
explosion (Amilia), impulsive onset (Farallon de Pajaros, Tori-shima,
and Macdonald), spectral banding (Macdonald and Saipan), sharp peaked
power spectrum of the T-phases indicative of magma-water interaction
(?) (Farallon de Pajaros, Saipan, and Macdonald). See Norris and Hart
(1970), and Johnson (1970) for more on Farallon de Pajaros and Macdonald.
1968
Duennebier,
F.K., Spectral variation of the T-phase, Hawaii Institute of Geophysics
Report, HIG-68-22, 18 pp., 1968.
Spectrograms
from various earthquakes are presented to illustrate spectral differences
(high versus low frequencies) between abyssal and bottom-slope generated
T-phases. Mechanisms for producing the variations in the different spectrograms
are reviewed with the conclusion being that the source of abyssal T-phases
is still a mystery i.e. sea-surface scattering is not the source of
abyssal T-phases. The role of ocean acoustics is recognized in this
paper.
Johnson,
R.H., And R.A. Norris, T-phase radiators in the western Aleutians,
Bull. Seism. Soc. Am., 58, 1-10, 1968.
T-phases
from aftershocks of the 1965 Rat Island earthquake are used to illustrate
that prominent submarine edifices can serve as radiation centers for
T-phases. In this case, six radiation points corresponding to promontories
along the Aleutian arc. An attempt is made to estimate the strengths
of the various radiators. The duration of the main shock is also estimated
with the caveat that one must take into account the contribution from
the different radiation sites (note: the Rat Island earthquake was very
large as was the fault length and the area of aftershocks).
Johnson,
R.H., R.A. Norris, and F.K. Duennebier, Abyssally generated T-phases,
in The Crust and Upper Mantle of the Pacific Area, edited by L.
Knopoff, C.L. Drake, and P.J. Hart, AGU Mono. 12, 70-78, 1968.
A
T-phase originating in the Aleutians generated a T-phases consisting
of two components a high frequency component which has a source location
similar to the computed epicenter, and a low frequency component similar
in form to classic down-slope propagated T-phases which has a source
location in the arc region. The low frequency wave is produced by propagation
of P away from the receiving stations, towards the arc, and then converted
to T by down-slope propagation. The high frequency component is termed
an abyssal T-phase and is the result of scattering from the sea surface.
Northrop,
J., An investigation of the relation between source characteristics
and T phases in the North Pacific area, Ph.D. Thesis, University of
Hawaii, 1968.
I
do not have this thesis although there is a copy in the Hawaii Institute
of Geophysics Library.
Northrop,
J., Comments on a paper by J.B. Shepherd and G.R. Robson, The source of
the T phase recorded in the eastern Caribbean on October 24, 1965, Bull.
Seism. Soc. Am., 58, 743-744, 1968.
In
this letter, it is argued primarily from a historical perspective, that
the "true" definition of a T-phase requires that the source be an earthquake.
I do not necessarily agree with this narrow definition otherwise one
could not write about P or S phases from explosions.
Northrop,
J., H.W. Menard, and F.K. Duennebier, Seismic and bathymetric evidence
of a fracture zone on Gorda Ridge, Science, 161, 688-690,
1968.
T-phases
from the Blanco Transform and Gorda Ridge fault are located by the Pacific
Missile Range network of SOFAR hydrophones. Ironically, the location
of the T-phase sources align themselves more closely on the Blanco Transform
and Gorda ridge, than epicenters from the USCGS it is later learned
that there is a systematic mislocation of epicenters in this area. Approximately
1000 T-phase events are located in this region with the majority of
the events located at the bend in the Gorda Ridge. This study is a precursor
to Hammond and Walker (1991).
Solovyev,
SL, R.S. Voronin, and S.I. Voronina, Seismic and hydroacoustic
data on T-waves (literature review), Tsunami Problem,
Publ. House Nauka, Moscow, 141 pp., 1968 (in Russian).
I
have not seen nor can I read this book. The title would indicate that
it contains useful information. I am also not sure if the authors first
name is spelled correctly (i.e. could by Soloviev). This paper is referenced
by Bath and Shahidi (1972).
1967
Cooke, R.J.S.,
Observations of the seismic T phase at Macquarie Island, New Zealand
J. Geol. Geophys., 10, 1212-1225, 1967.
T
phases from as far away as South America are reported a
large number of events from the South Pacific Cordillera
(aka Pacific-Antarctic Ridge and Southern East Pacific Rise)
are also observed. Several interesting points are made in
this paper. Earthquakes along the Macquarie Ridge (as reported
by USCGS) do not generate T phases that are recorded on
Macquarie Island possibly due to the presence of topographic
barriers in the SOFAR channel. Secondly, T phases that reflected
off of bathymetric features (i.e. Campbell Plateau) are
recorded.
Duennebier,
F.K., And R.H. Johnson, T-phase sources and earthquake epicenters
in the Pacific basin, Hawaii Institute of Geophysics Report,
HIG-67-24, 16 pp., 1967.
Two
years worth of T-phase sources in the Pacific are identified in this
technical report the total number exceeds 20,000 events. A comparison
is made with the earthquake epicenters listed by the USCGS. It is shown
that for various regions of the Pacific, T-phases are a better indicator
of the seismic activity than the teleseismically determined epicenters.
Johnson,
R.H., R.A. Norris, and F.K. Duennebier, Abssally generated T phases, Hawaii
Institute of Geophysics Report, HIG-67-1, 12 pp., 1967.
See
Johnson, Norris, and Duennebier (1968) for an equivalent reference.
Kibblewhite,
A.C., Note on another active seamount in the south Kermadec
ridge group, New Zealand J. SCI, 10, 68-69,
1967.
Another
seamount (Rumble III) north of New Zealand is found to be active base
on acoustic noise measurements. A fourth one, Rumble IV is really Rumble
III as proposed in a later paper (Hall, 1985).
Norris,
R.A., And R.H. Johnson, Submarine volcanic eruptions recently
located in the Pacific by SOFAR hydrophones, Hawaii Institute
of Geophysics Report, HIG-67-22, 16 pp.,
1967.
See
Norris and Johnson (1970) for an equivalent reference.
Shepherd,
J.B., And G.R. Robson, 1967, The source of the T-phase recorded
in the eastern Caribbean on October 24, 1965, Bull. Seism.
Soc. Am., 57, 227-234, 1967.
High
frequency T-phases recorded by short-period seismographs in the Caribbean
is estimated to be from a shallow submarine volcano north of Grenada.
It is proposed that collapsing steam bubbles are the acoustic source
of this disturbance. An attempt is made to estimate the energy of the
T-phases and to convert this number to energy produced by steam production.
Some T-phases were felt on distant islands.
1966
Johnson,
R.H., Routine location of T-phase sources in the Pacific, Bull. Seism.
Soc. Am., 56, 109-118, 1966.
A
least-squares method for calculating the radiation location and origin
time of T-phases is presented (see Johnson 1965 for an equivalent reference).
The method used by HIG to compute T-phase magnitude is also presented
(i.e. take second largest of four observations) the power of the T-phase
is normalized to a prescribed distance (30° from the source). Velocity
across the Pacific is described by a second order polynomial in latitude
and longitude, spherical earth is assumed, four observations are used.
Johnson,
R.H., And R.A. Norris, T-phase radiators in the western Aleutians,
Hawaii Institute of Geophysics Report, HIG-66-4, 13
pp., 1966.
See
Johnson and Norris (1968) for an equivalent reference.
Johnson,
R.H., And J. Northrop, A comparison of earthquake magnitude
with T-phase strength, Bull. Seism. Soc. Am., 56,
119-124, 1966.
Using
the Pacific hydrophone network, 10 times more events are
detected from the Aleutian Island region than that listed
by the US Coast and Geodetic Survey. By comparing T-phase
level is dB, S, with the observed earthquake magnitude,
M, (when possible), a crude relationship can be formulated
where, S = 20 M - 52. However, since many "large" T-phases
are not recorded on the land-based seismometers, many events
represent highly efficient excitation of T. Conclusions
reached are that the use of T-phases extends the detection
level of Aleutian earthquakes down 0.7 magnitude, and that
there are as many event over and below M = 3.6 that can
be located by T-phases.
Kibblewhite,
AC, Detection and location of a new underwater volcano, Nature,
210, 938-939, 1966.
Short
note on acoustic signals recorded from a possible underwater
volcano (Rumble III) northeast of New Zealand. A better
reference would be Kibblewhite, N.Z.J. SCI, 1966.
Kibblewhite,
AC, The acoustic detection and location of an underwater volcano,
New Zealand J. SCI, 9, 178-199, 1966.
Sea
noise spectra recorded on hydrophones east of North Island, New Zealand,
lead to the detection of underwater volcanic activity 150 miles ENE
of Great Barrier Island. The spectra reveal a signal whose frequencies
range from 20 to 400 Hz.
Kibblewhite,
AC, and D.J. Barnes, The location of an underwater volcano
by passive acoustic detection system, US Navy J. Underwater
Acoust., 16, 353, 1966 (Confidential).
This
paper is from a classified (confidential) journal which I have not seen.
I assume that this article is similar to Kibblewhite (1966) except that
it contains additional information about the instrumentation.
1965
Anonymous,
T-phase observer's manual, Hawaii Institute of Geophysics, 8 pp,
1965.
This
is an in-house user's guide for analyzing T-phases at the Hawaii Institute
of Geophysics.
Brazee,
R.J., A study of T phases in the Aleutian earthquake series of March and
April 1957, Earthquake Notes, 36, 9-14, 1965.
T-phases
from Aleutian earthquakes are used to evaluate past hypotheses. The
basic conclusions are that earthquake magnitude is not the sole determiner
of T-phase generation, conversion from P to T can occur distant from
the source, and that conversion to T is best when it occurs in the SOFAR
channel.
Johnson,
R.H., A program for routine location of T-phase sources in the Pacific,
Hawaii Institute of Geophysics Report, HIG-65-6, 17 pp.,
1965.
The
technique for locating T-phase sources by means of triangulation is
presented (See Johnson, 1966 for an equivalent reference).
Northrop,
J., T phases from 80 Alaska earthquakes, March 28-31, 1964, Bull. Seism.
Soc. Am., 55, 59-63, 1965.
This
study describes T-phases from the main and aftershocks of the Good Friday
Alaskan earthquake as recorded at Point Sur, California. It was observed
that hypocenters (as determined by USCGS) for events located under the
continent slope, were more efficient in generating T-phases this is
more confirmation of the proposal of Wadati and Inouye (1953, 1956).
Local topographic effects also contribute to the relative excitation
of P to T conversion. Note: the T-phase from the main shock lasted 2
1/2 hours. See Northrop, 1972 for additional results.
Northrop,
J., and R.H. Johnson, Seismic waves recorded in the north Pacific from
Flip, J. Geophys. Res., 70, 311-318, 1965.
T
phases from earthquakes and shots distributed along the margins of the
Pacific (New Britain, Aleutians, and Hokkaido) are recorded by hydrophones
suspended from Flip and also by the Pacific Missile Range network. Since
T phase are recorded on hydrophones positioned at widely varying depths
(e.g. 80 m for Flip, and 5500 m for Wake), it is concluded that T phase
energy is not confined to the SOFAR axis (i.e. propagation by normal
modes). There was also evidence of dispersion of the waves.
Wadati,
K., and H. Sato, Propagation of T-waves in the Pacific Ocean, Geophys.
Mag. Tokyo, 32, 255-271, 1965.
This
paper is essentially a data dump of information pertaining to T-phases
recorded at the Torishima seismic station from events around Japan,
Chile, and Lituya Bay. Included are data recorded in Hawaii from the
Chilean earthquakes. More credence is given to the notion that intermediate
depth earthquakes are more effective in generating T-phases. On a side-note,
the T-phase from one of the Lituya Bay earthquakes was felt in Japan.
1964
De, US, Observations
on T-phase, Ind. J. Meterol. Geophys., 15, 662-664,
1964.
Two
more T-phases from the Andaman Island earthquakes are reported. Not
much else to say about this paper.
Gupta,
I.N., Discussion of "Source-mechanism from spectra of long-period seismic
surface waves: 3. The Alaska earthquake of July 19, 1958" by A. Ben-Menahem
and M.N. Toksoz, Bull. Seism. Soc. Am., 54, 2085-2086, 1964.
Correction
to the equations used by Ben-Menahem and Toksoz are presented which
results in a factor of two increase in the estimated duration time of
the T-phase due to faulting. This new value is the same as the difference
in the T-phase duration time of the main versus an aftershock. Northrop
(1972) later shows that the equation used by Gupta is not applicable
for T-phases measured on SOFAR hydrophones for the Good Friday Alaskan
Earthquake.
Johnson,
R.H., Earthquakes located by T phases during the VELA UNIFORM Aleutian
Islands experiment, Hawaii Institute of Geophysics Report, HIG-64-23,
11 pp., 1964.
Earthquakes
recorded on the Pacific Missile Range network of hydrophones during
the VELA UNIFORM (essentially a calibration experiment in the Aleutians)
are presented a total of 654 events were detected. It is estimated that
the detection threshold of the hydrophone network is earthquake magnitude
3. This report is a precursor of the later work to be performed by Johnson
and his co-workers at HIG.
1963
Aubrat, J.,
Ondes T reflechies dans la Mer Des Antilles, Ann. Geophys.,19,
386-405, 1963 (in French).
T-phases
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