No spreading across the Southern Juan de Fuca Ridge axial cleft during 1994-1996

No spreading across the Southern Juan de Fuca Ridge axial cleft during 1994-1996

Direct‐path acoustic measurements between seafloor transponders observed no significant extension (−10±14 mm/yr) from August 1994 to September 1996 at the southern Juan de Fuca Ridge (44°40′ N and 130°20′ W). The acoustic path for the measurement is a 691‐m baseline straddling the axial cleft, which...

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Bibliographic Details
Published in:Geophysical research letters Vol. 26; no. 16; pp. 2525 - 2528
Main Authors: Chadwell, C. David, Hildebrand, John A., Spiess, Fred N., Morton, Janet L., Normark, William R., Reiss, Carol A.
Format: Journal Article
Language:English
Published: Washington, DC Blackwell Publishing Ltd 15-08-1999
American Geophysical Union
Subjects:
Earth sciences
Earth, ocean, space
Exact sciences and technology
Marine
Tectonics. Structural geology. Plate tectonics
Juan de Fuca Ridge
East Pacific Rise
INE, Pacific, Juan de Fuca Ridge
Pacific Plate
acoustical surveys
plate divergence
mid-ocean ridges
extension tectonics
sea-floor spreading
deformation
Pacific Ocean
plate boundaries
Juan de Fuca Plate
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Summary:Direct‐path acoustic measurements between seafloor transponders observed no significant extension (−10±14 mm/yr) from August 1994 to September 1996 at the southern Juan de Fuca Ridge (44°40′ N and 130°20′ W). The acoustic path for the measurement is a 691‐m baseline straddling the axial cleft, which bounds the Pacific and Juan de Fuca plates. Given an expected full‐spreading rate of 56 mm/yr, these data suggest that extension across this plate boundary occurs episodically within the narrow (∼ 1 km) region of the axial valley floor, and that active deformation is occurring between the axial cleft and the plate interior. A cleft‐parallel 714‐m baseline located 300 m to the west of the cleft on the Pacific plate monitored system performance and, as expected, observed no motion (+5±7 mm/yr) between the 1994 and 1996 surveys.
Bibliography:istex:EDC84D1F96CE38A007749AEBD8D9A0B9A7818872
ArticleID:1999GL900570
ark:/67375/WNG-CMQHJ2Q6-9
ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0094-8276
1944-8007
DOI:10.1029/1999GL900570