@article{Chesley.2021,
title = {Fluid-rich subducting topography generates anomalous forearc porosity},
author = {Christine Chesley and Samer Naif and Kerry Key and Dan Bassett},
url = {https://www.nature.com/articles/s41586-021-03619-8.epdf?sharing_token=059dEpg3Ed0LSl8d02FaDdRgN0jAjWel9jnR3ZoTv0M_rJgybuzy9QY1Pp-7852_sl1dUqsZYNhDbIkAbAwN8O00dlhHX0kHWAqHdpqZsFD8QgiZoZHW8WJbEVUSVahCUzKCDjMjf_MTwwA70y77ZzabPEx99qB99b1SDa08GkI%3D},
doi = {10.1038/s41586-021-03619-8},
issn = {0028-0836},
year = {2021},
date = {2021-01-01},
journal = {Nature},
volume = {595},
number = {7866},
pages = {255--260},
abstract = {The role of subducting topography on the mode of fault slip—particularly whether it hinders or facilitates large megathrust earthquakes—remains a controversial topic in subduction dynamics1–5. Models have illustrated the potential for subducting topography to severely alter the structure, stress state and mechanics of subduction zones4,6; however, direct geophysical imaging of the complex fracture networks proposed and the hydrology of both the subducting topography and the associated upper plate damage zones remains elusive. Here we use passive and controlled-source seafloor electromagnetic data collected at the northern Hikurangi Margin, New Zealand, to constrain electrical resistivity in a region of active seamount subduction. We show that a seamount on the incoming plate contains a thin, low-porosity basaltic cap that traps a conductive matrix of porous volcaniclastics and altered material over a resistive core, which allows 3.2 to 4.7 times more water to subduct, compared with normal, unfaulted oceanic lithosphere. In the forearc, we image a sediment-starved plate interface above a subducting seamount with similar electrical structure to the incoming plate seamount. A sharp resistive peak within the subducting seamount lies directly beneath a prominent upper plate conductive anomaly. The coincidence of this upper plate anomaly with the location of burst-type repeating earthquakes and seismicity associated with a recent slow slip event7 directly links subducting topography to the creation of fluid-rich damage zones in the forearc that alter the effective normal stress at the plate interface by modulating the fluid overpressure. In addition to severely modifying the structure and physical conditions of the upper plate, subducting seamounts represent an underappreciated mechanism for transporting a considerable flux of water to the forearc and deeper mantle. Electromagnetic data collected at the northern Hikurangi Margin, New Zealand show that a seamount on the incoming plate allows more water to subduct, compared with normal, unfaulted oceanic lithosphere.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Chesley:2019fv,
title = {Crustal Cracks and Frozen Flow in Oceanic Lithosphere Inferred From Electrical Anisotropy},
author = {Christine Chesley and Kerry Key and Steven Constable and James Behrens and Lucy MacGregor},
url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2019/12/Chesley_et_al-2019-Geochemistry_Geophysics_Geosystems.pdf},
year = {2019},
date = {2019-12-01},
journal = {Geochemistry Geophysics Geosystems},
volume = {20},
number = {138},
pages = {21},
abstract = {Geophysical observations of anisotropy in oceanic lithosphere offer insight into the formation and evolution of tectonic plates. Seismic anisotropy is well studied but electrical anisotropy remains poorly understood, especially in the crust and uppermost mantle. Here we characterize electrical anisotropy in 33 Ma Pacific lithosphere using controlled‐source electromagnetic data that are highly sensitive to lithospheric azimuthal anisotropy. Our data reveal that the crust is ∼18–36 times more conductive in the paleo mid‐ocean ridge direction than the perpendicular paleo‐spreading direction, while in the uppermost mantle conductivity is ∼29 times higher in the paleo‐spreading direction. We propose that the crustal anisotropy results from subvertical porosity created by ridge‐parallel normal faulting during extension of the young crust and thermal stress‐driven cracking from cooling of mature crust. The magnitude of uppermost mantle anisotropy is consistent with recent experimental results showing strong electrical anisotropy in sheared olivine, suggesting its paleo‐spreading orientation results from sub‐Moho mantle shearing during plate formation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Chesley:2012fv,
title = {The 1707 Mw 8.7 Hoei earthquake triggered the largest historical eruption of Mt. Fuji},
author = {Christine Chesley and Peter C. LaFemina and Christine Puskas and Daisuke Kobayashi},
doi = {https://doi.org/10.1029/2012GL053868},
year = {2012},
date = {2012-12-22},
journal = {Geophysical Research Letters},
volume = {39},
number = {24},
pages = {5},
abstract = {[1] Studies in magma‐tectonics point to a spatiotemporal correlation between earthquakes and volcanic eruptions. Here, we examine the correlation between two great Japanese earthquakes, the 1703 Mw 8.2 Genroku and 1707 Mw 8.7 Hoei, and Mt. Fuji's explosive (VEI 5) Hoei eruption, 49 days after the 1707 earthquake. We model the static stress changes and dilatational strain imparted on the Mt. Fuji magmatic system due to each earthquake to determine if these mechanisms enhanced the potential for eruption. Our results show that both earthquakes clamped the dike from 8 km to the surface and compressed magma chambers at 8 km and 20 km depths. The 1707 earthquake decreased the normal stress on the dike at 20 km, the proposed depth of a basaltic magma chamber, by 1.06 bars (0.106 MPa). We hypothesize that the stress change and strain generated by the 1707 earthquake triggered the eruption of Mt. Fuji by permitting opening of the dike and ascent of basaltic magma from 20 km into andesitic and dacitic magma chambers located at 8 km depth. The injection of basaltic magma into the more evolved magmatic system induced magma mixing and a Plinian eruption ensued.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}