@article {chadwick_geodetic_2022,
	title = {Geodetic Monitoring at Axial Seamount Since Its 2015 Eruption Reveals a Waning Magma Supply and Tightly Linked Rates of Deformation and Seismicity},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {23},
	number = {1},
	year = {2022},
	note = {Place: Washington Publisher: Amer Geophysical Union WOS:000751308100015},
	pages = {e2021GC010153},
	abstract = {Axial Seamount is a basaltic hot spot volcano with a summit caldera at a depth of similar to 1,500 m below sea level, superimposed on the Juan de Fuca spreading ridge, giving it a robust and continuous magma supply. Axial erupted in 1998, 2011, and 2015, and is monitored by a cabled network of instruments including bottom pressure recorders and seismometers. Since its last eruption, Axial has re-inflated to 85\%-90\% of its pre-eruption level. During that time, we have identified eight discrete, short-term deflation events of 1-4 cm over 1-3 weeks that occurred quasi-periodically, about every 4-6 months between August 2016 and May 2019. During each short-term deflation event, the rate of earthquakes dropped abruptly to low levels, and then did not return to higher levels until reinflation had resumed and returned near its previous high. The long-term geodetic monitoring record suggests that the rate of magma supply has varied by an order of magnitude over decadal time scales. There was a surge in magma supply between 2011 and 2015, causing those two eruptions to be closely spaced in time and the supply rate has been waning since then. This waning supply has implications for eruption forecasting and the next eruption at Axial still appears to be 4-9 years away. We also show that the number of earthquakes per unit of uplift has increased exponentially with total uplift since the 2015 eruption, a pattern consistent with a mechanical model of cumulative rock damage leading to bulk failure during magma accumulation between eruptions.},
	keywords = {bottom pressure recorders, de-fuca ridge, eruption forecasting, galapagos, ground deformation, high-resolution, inflation, kilauea volcano, lava flows, midocean ridge, ocean bottom seismometers, OOI cabled observatory, precursors, seafloor geodesy, sierra-negra-volcano, submarine volcano monitoring},
	doi = {10.1029/2021GC010153},
	url = {https://www.webofscience.com/api/gateway?GWVersion=2\&SrcAuth=DOISource\&SrcApp=WOS\&KeyAID=10.1029\%2F2021gc010153\&DestApp=DOI\&SrcAppSID=USW2EC0AF0FhQ3gq3aJ9tUIgn6Kiy\&SrcJTitle=GEOCHEMISTRY+GEOPHYSICS+GEOSYSTEMS\&DestDOIRegistrantName=American+Geophysical+Uni},
	author = {Chadwick, William W. and Wilcock, William S. D. and Nooner, Scott L. and Beeson, Jeffrey W. and Sawyer, Audra M. and Lau, T.-k}
}
@article {fluegel_magnetization_2022,
	title = {The Magnetization of an Underwater Caldera: A Time-Lapse Magnetic Anomaly Study of Axial Seamount},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {17},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL100008},
	pages = {e2022GL100008},
	abstract = {Axial Seamount in the northeast Pacific erupted in 2015, 2011, and 1998. Although monitored by the Regional Cabled Array of the Ocean Observatory Initiative, few magnetic surveys have been conducted over the region. This study uses high-resolution magnetic data over the seamount collected by autonomous underwater vehicle Sentry during three years (2015, 2017, and 2020). The goal is to investigate whether there are temporal changes in the near-surface magnetic field observable over the time scale of one volcanic cycle. We compare magnetic maps from repeated tracklines from each year. We find maps of the yearly difference in magnetization show coherent patterns that are not random. The central region of the caldera has become more magnetic during recent years, suggesting cooling of the surficial lava flows since 2015. Sentry data are more sensitive to shallow crustal structure compared to sea surface data which show longer wavelength anomalies extending deeper into the crust.},
	keywords = {magnetism, monitoring, seamounts, volcanic hazards, volcanology},
	issn = {1944-8007},
	doi = {10.1029/2022GL100008},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL100008},
	author = {Fluegel, Bailey and Tivey, Maurice and Biasi, Joseph and Chadwick Jr., William W. and Nooner, Scott L.}
}
@article {RN273,
	title = {Geodetic Monitoring at Axial Seamount Since its 2015 Eruption Reveals a Waning Magma Supply and Tightly Linked Rates of Deformation and Seismicity},
	journal = {Geochemistry Geophysics Geosystems},
	year = {2021},
	type = {Journal Article},
	doi = {10.1029/2021gc010153},
	url = {https://app.dimensions.ai/details/publication/pub.1144167182},
	author = {Chadwick, William W. and Wilcock, William S. D. and Nooner, Scott L. and Beeson, Jeff W. and Sawyer, Audra M. and Lau, T. -K}
}
@article {RN131,
	title = {Revised Magmatic Source Models for the 2015 Eruption at Axial Seamount Including Estimates of Fault-Induced Deformation},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {4},
	year = {2020},
	type = {Journal Article},
	abstract = {Axial Seamount is an active submarine volcano located at the intersection of the Cobb hot spot and the Juan de Fuca Ridge (45{\textdegree}57'N, 130{\textdegree}01'W). Bottom pressure recorders captured co-eruption subsidence of 2.4{\textendash}3.2 m in 1998, 2011, and 2015, and campaign-style pressure surveys every 1{\textendash}2 years have provided a long-term time series of inter-eruption re-inflation. The 2015 eruption occurred shortly after the Ocean Observatories Initiative (OOI) Cabled Array came online providing real-time seismic and deformation observations for the first time. Nooner and Chadwick (2016, https://doi.org/10.1126/science.aah4666) used the available vertical deformation data to model the 2015 eruption deformation source as a steeply dipping prolate-spheroid, approximating a high-melt zone or conduit beneath the eastern caldera wall. More recently, Levy et al. (2018, https://doi.org/10.1130/G39978.1) used OOI seismic data to estimate dip-slip motion along a pair of outward-dipping caldera ring faults. This fault motion complicates the deformation field by contributing up to several centimeters of vertical seafloor motion. In this study, fault-induced surface deformation was calculated from the slip estimates of Levy et al. (2018, https://doi.org/10.1130/G39978.1) then removed from vertical deformation data prior to model inversions. Removing fault motion resulted in an improved model fit with a new best-fitting deformation source located 2.11 km S64{\textdegree}W of the source of Nooner and Chadwick (2016, https://doi.org/10.1126/science.aah4666) with similar geometry. This result shows that ring fault motion can have a significant impact on surface deformation, and future modeling efforts need to consider the contribution of fault motion when estimating the location and geometry of subsurface magma movement at Axial Seamount.},
	doi = {10.1029/2020jb019356},
	url = {https://app.dimensions.ai/details/publication/pub.1125839587},
	author = {Hefner, William L. and Nooner, Scott L. and Chadwick, William W. and Bohnenstiehl, DelWayne R.}
}
@article {RN161,
	title = {Triggering of eruptions at Axial Seamount, Juan de Fuca Ridge},
	journal = {Scientific Reports},
	volume = {10},
	number = {1},
	year = {2020},
	pages = {10219},
	type = {Journal Article},
	abstract = {The submarine volcano Axial Seamount has exhibited an inflation predictable eruption cycle, which allowed for the successful forecast of its 2015 eruption. However, the exact triggering mechanism of its eruptions remains ambiguous. The inflation predictable eruption pattern suggests a magma reservoir pressure threshold at which eruptions occur, and as such, an overpressure eruption triggering mechanism. However, recent models of volcano unrest suggest that eruptions are triggered when conditions of critical stress are achieved in the host rock surrounding a magma reservoir. We test hypotheses of eruption triggering using 3-dimensional finite element models which track stress evolution and mechanical failure in the host rock surrounding the Axial magma reservoir. In addition, we provide an assessment of model sensitivity to various temperature and non-temperature-dependent rheologies and external tectonic stresses. In this way, we assess the contribution of these conditions to volcanic deformation, crustal stress evolution, and eruption forecasts. We conclude that model rheology significantly impacts the predicted timing of through-going failure and eruption. Models consistently predict eruption at a reservoir pressure threshold of 12{\textendash}14 MPa regardless of assumed model rheology, lending support to the interpretation that eruptions at Axial Seamount are triggered by reservoir overpressurization.

},
	doi = {10.1038/s41598-020-67043-0},
	url = {https://app.dimensions.ai/details/publication/pub.1128680799 https://www.nature.com/articles/s41598-020-67043-0.pdf},
	author = {Cabaniss, Haley E. and Gregg, Patricia M. and Nooner, Scott L. and Chadwick, William W.}
}
