A seismic swarm and regional hydrothermal and hydrologic perturbations: The northern Endeavour segment, February 2005

Emilie E E Hooft, Hemalinee Patel, William Wilcock, Keir Becker, David Butterfield, Earl Davis, Robert Dziak, Katherine Inderbitzen, Marvin Lilley, Paul McGill, Douglas Toomey, Debra Stakes

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The February 2005 swarm at the overlapping spreading center (OSC) on the northern end of the Endeavour segment is the first swarm on the Juan de Fuca Ridge recorded on a local seafloor seismic network. The swarm included several larger earthquakes and caused triggered seismicity and a hydrothermal response in the Endeavour vent fields as well as regional-scale hydrologic pressure perturbations. The spatial and temporal pattern of over 6000 earthquakes recorded during this seismic sequence is complex. Small-magnitude events dominate, and seismicity rates wax and wane, indicating a magmatic process. The main swarm initiates at the northern end of the Endeavour ridge. However, most of the moment release, including six strike-slip events, occurs in the southwest Endeavour Valley, where the swarm epicenters generally migrate south. The main swarm is contemporaneous with a hydrologic pressure response at four sealed seafloor boreholes, ∼25-105 km away. We infer that the seismic sequence is driven by a largely aseismic magma intrusion at the northern Endeavour axis. Resulting stress changes trigger slip on tectonic faults and possibly dike propagation at the opposing limb of the Endeavour OSC in the southwest Endeavour Valley, consistent with the eventual decapitation of the Endeavour by the West Valley segment. Furthermore, 2.5 days after the start of the main swarm, seismicity is triggered beneath the Endeavour vent fields, and temperature increases at a diffuse vent in the Mothra field. We infer that this delayed response is due to a hydrologic pressure pulse that diffuses away from the main magma intrusion.

Original languageEnglish (US)
Article numberQ12015
JournalGeochemistry, Geophysics, Geosystems
Volume11
Issue number12
DOIs
StatePublished - 2010

Fingerprint

Vents
seismicity
spreading center
perturbation
valley
Earthquakes
seafloor
magma
earthquake
Levees
Waxes
stress change
vents
Tectonics
wax
Boreholes
earthquake epicenter
valleys
limb
dike

Keywords

  • earthquake swarm
  • Endeavour ridge
  • hydrologic response
  • hydrothermal response
  • magma intrusion
  • overlapping spreading center

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

A seismic swarm and regional hydrothermal and hydrologic perturbations : The northern Endeavour segment, February 2005. / Hooft, Emilie E E; Patel, Hemalinee; Wilcock, William; Becker, Keir; Butterfield, David; Davis, Earl; Dziak, Robert; Inderbitzen, Katherine; Lilley, Marvin; McGill, Paul; Toomey, Douglas; Stakes, Debra.

In: Geochemistry, Geophysics, Geosystems, Vol. 11, No. 12, Q12015, 2010.

Research output: Contribution to journalArticle

Hooft, EEE, Patel, H, Wilcock, W, Becker, K, Butterfield, D, Davis, E, Dziak, R, Inderbitzen, K, Lilley, M, McGill, P, Toomey, D & Stakes, D 2010, 'A seismic swarm and regional hydrothermal and hydrologic perturbations: The northern Endeavour segment, February 2005', Geochemistry, Geophysics, Geosystems, vol. 11, no. 12, Q12015. https://doi.org/10.1029/2010GC003264
Hooft, Emilie E E ; Patel, Hemalinee ; Wilcock, William ; Becker, Keir ; Butterfield, David ; Davis, Earl ; Dziak, Robert ; Inderbitzen, Katherine ; Lilley, Marvin ; McGill, Paul ; Toomey, Douglas ; Stakes, Debra. / A seismic swarm and regional hydrothermal and hydrologic perturbations : The northern Endeavour segment, February 2005. In: Geochemistry, Geophysics, Geosystems. 2010 ; Vol. 11, No. 12.
@article{4edcd6e4c92a482ca0cb63b987ffafd8,
title = "A seismic swarm and regional hydrothermal and hydrologic perturbations: The northern Endeavour segment, February 2005",
abstract = "The February 2005 swarm at the overlapping spreading center (OSC) on the northern end of the Endeavour segment is the first swarm on the Juan de Fuca Ridge recorded on a local seafloor seismic network. The swarm included several larger earthquakes and caused triggered seismicity and a hydrothermal response in the Endeavour vent fields as well as regional-scale hydrologic pressure perturbations. The spatial and temporal pattern of over 6000 earthquakes recorded during this seismic sequence is complex. Small-magnitude events dominate, and seismicity rates wax and wane, indicating a magmatic process. The main swarm initiates at the northern end of the Endeavour ridge. However, most of the moment release, including six strike-slip events, occurs in the southwest Endeavour Valley, where the swarm epicenters generally migrate south. The main swarm is contemporaneous with a hydrologic pressure response at four sealed seafloor boreholes, ∼25-105 km away. We infer that the seismic sequence is driven by a largely aseismic magma intrusion at the northern Endeavour axis. Resulting stress changes trigger slip on tectonic faults and possibly dike propagation at the opposing limb of the Endeavour OSC in the southwest Endeavour Valley, consistent with the eventual decapitation of the Endeavour by the West Valley segment. Furthermore, 2.5 days after the start of the main swarm, seismicity is triggered beneath the Endeavour vent fields, and temperature increases at a diffuse vent in the Mothra field. We infer that this delayed response is due to a hydrologic pressure pulse that diffuses away from the main magma intrusion.",
keywords = "earthquake swarm, Endeavour ridge, hydrologic response, hydrothermal response, magma intrusion, overlapping spreading center",
author = "Hooft, {Emilie E E} and Hemalinee Patel and William Wilcock and Keir Becker and David Butterfield and Earl Davis and Robert Dziak and Katherine Inderbitzen and Marvin Lilley and Paul McGill and Douglas Toomey and Debra Stakes",
year = "2010",
doi = "10.1029/2010GC003264",
language = "English (US)",
volume = "11",
journal = "Geochemistry, Geophysics, Geosystems",
issn = "1525-2027",
publisher = "American Geophysical Union",
number = "12",

}

TY - JOUR

T1 - A seismic swarm and regional hydrothermal and hydrologic perturbations

T2 - The northern Endeavour segment, February 2005

AU - Hooft, Emilie E E

AU - Patel, Hemalinee

AU - Wilcock, William

AU - Becker, Keir

AU - Butterfield, David

AU - Davis, Earl

AU - Dziak, Robert

AU - Inderbitzen, Katherine

AU - Lilley, Marvin

AU - McGill, Paul

AU - Toomey, Douglas

AU - Stakes, Debra

PY - 2010

Y1 - 2010

N2 - The February 2005 swarm at the overlapping spreading center (OSC) on the northern end of the Endeavour segment is the first swarm on the Juan de Fuca Ridge recorded on a local seafloor seismic network. The swarm included several larger earthquakes and caused triggered seismicity and a hydrothermal response in the Endeavour vent fields as well as regional-scale hydrologic pressure perturbations. The spatial and temporal pattern of over 6000 earthquakes recorded during this seismic sequence is complex. Small-magnitude events dominate, and seismicity rates wax and wane, indicating a magmatic process. The main swarm initiates at the northern end of the Endeavour ridge. However, most of the moment release, including six strike-slip events, occurs in the southwest Endeavour Valley, where the swarm epicenters generally migrate south. The main swarm is contemporaneous with a hydrologic pressure response at four sealed seafloor boreholes, ∼25-105 km away. We infer that the seismic sequence is driven by a largely aseismic magma intrusion at the northern Endeavour axis. Resulting stress changes trigger slip on tectonic faults and possibly dike propagation at the opposing limb of the Endeavour OSC in the southwest Endeavour Valley, consistent with the eventual decapitation of the Endeavour by the West Valley segment. Furthermore, 2.5 days after the start of the main swarm, seismicity is triggered beneath the Endeavour vent fields, and temperature increases at a diffuse vent in the Mothra field. We infer that this delayed response is due to a hydrologic pressure pulse that diffuses away from the main magma intrusion.

AB - The February 2005 swarm at the overlapping spreading center (OSC) on the northern end of the Endeavour segment is the first swarm on the Juan de Fuca Ridge recorded on a local seafloor seismic network. The swarm included several larger earthquakes and caused triggered seismicity and a hydrothermal response in the Endeavour vent fields as well as regional-scale hydrologic pressure perturbations. The spatial and temporal pattern of over 6000 earthquakes recorded during this seismic sequence is complex. Small-magnitude events dominate, and seismicity rates wax and wane, indicating a magmatic process. The main swarm initiates at the northern end of the Endeavour ridge. However, most of the moment release, including six strike-slip events, occurs in the southwest Endeavour Valley, where the swarm epicenters generally migrate south. The main swarm is contemporaneous with a hydrologic pressure response at four sealed seafloor boreholes, ∼25-105 km away. We infer that the seismic sequence is driven by a largely aseismic magma intrusion at the northern Endeavour axis. Resulting stress changes trigger slip on tectonic faults and possibly dike propagation at the opposing limb of the Endeavour OSC in the southwest Endeavour Valley, consistent with the eventual decapitation of the Endeavour by the West Valley segment. Furthermore, 2.5 days after the start of the main swarm, seismicity is triggered beneath the Endeavour vent fields, and temperature increases at a diffuse vent in the Mothra field. We infer that this delayed response is due to a hydrologic pressure pulse that diffuses away from the main magma intrusion.

KW - earthquake swarm

KW - Endeavour ridge

KW - hydrologic response

KW - hydrothermal response

KW - magma intrusion

KW - overlapping spreading center

UR - http://www.scopus.com/inward/record.url?scp=79251572633&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79251572633&partnerID=8YFLogxK

U2 - 10.1029/2010GC003264

DO - 10.1029/2010GC003264

M3 - Article

AN - SCOPUS:79251572633

VL - 11

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

SN - 1525-2027

IS - 12

M1 - Q12015

ER -