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Fault Zone Guided Wave generation on the locked, late interseismic Alpine Fault, New Zealand

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journal contribution
posted on 09.02.2021, 19:09 by JD Eccles, AK Gulley, PE Malin, CM Boese, John TownendJohn Townend, Rupert SutherlandRupert Sutherland
© 2015. American Geophysical Union. All Rights Reserved. Fault Zone Guided Waves (FZGWs) have been observed for the first time within New Zealand's transpressional continental plate boundary, the Alpine Fault, which is late in its typical seismic cycle. Ongoing study of these phases provides the opportunity to monitor interseismic conditions in the fault zone. Distinctive dispersive seismic codas (~7-35Hz) have been recorded on shallow borehole seismometers installed within 20m of the principal slip zone. Near the central Alpine Fault, known for low background seismicity, FZGW-generating microseismic events are located beyond the catchment-scale partitioning of the fault indicating lateral connectivity of the low-velocity zone immediately below the near-surface segmentation. Initial modeling of the low-velocity zone indicates a waveguide width of 60-200m with a 10-40% reduction in S wave velocity, similar to that inferred for the fault core of other mature plate boundary faults such as the San Andreas and North Anatolian Faults.

History

Preferred citation

Eccles, J. D., Gulley, A. K., Malin, P. E., Boese, C. M., Townend, J. & Sutherland, R. (2015). Fault Zone Guided Wave generation on the locked, late interseismic Alpine Fault, New Zealand. Geophysical Research Letters, 42(14), 5736-5743. https://doi.org/10.1002/2015GL064208

Journal title

Geophysical Research Letters

Volume

42

Issue

14

Publication date

01/01/2015

Pagination

5736-5743

Publisher

American Geophysical Union (AGU)

Publication status

Published

Online publication date

16/07/2015

ISSN

0094-8276

eISSN

1944-8007

Language

en