@article {Neira2016,
	title = {{Cross-hole tracer experiment reveals rapid fluid flow and low effective porosity in the upper oceanic crust}},
	journal = {Earth and Planetary Science Letters},
	volume = {450},
	year = {2016},
	pages = {355{\textendash}365},
	abstract = {Numerous field, laboratory, and modeling studies have explored the flows of fluid, heat, and solutes during seafloor hydrothermal circulation, but it has been challenging to determine transport rates and flow directions within natural systems. Here we present results from the first cross-hole tracer experiment in the upper oceanic crust, using four subseafloor borehole observatories equipped with autonomous samplers to track the transport of a dissolved tracer (sulfur hexafluoride, SF6) injected into a ridge-flank hydrothermal system. During the first three years after tracer injection, SF6 was transported both north and south through the basaltic aquifer. The observed tracer transport rate of \~{}2{\textendash}3 m/day is orders of magnitude greater than bulk rates of flow inferred from thermal and chemical observations and calculated with coupled fluid-heat flow simulations. Taken together, these results suggest that the effective porosity of the upper volcanic crust through which much tracer was transported is {\textless}1{\%}, with fluid flowing rapidly along a few well-connected channels. This is consistent with the heterogeneous (layered, faulted, and/or fractured) nature of the volcanic upper oceanic crust.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.epsl.2016.06.048},
	author = {Neira, N M and Clark, J F and Fisher, A T and Wheat, C G and Haymon, R M and Becker, K}
}
@article {White2002,
	title = {{Correlation between volcanic and tectonic segmentation of fast-spreading ridges: Evidence from volcanic structures and lava flow morphology on the East Pacific Rise at 9 degrees -10 degrees N}},
	journal = {Journal of Geophysical Research},
	volume = {107},
	number = {B8},
	year = {2002},
	pages = {Article no. 2173},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Argo (Remotely Operated Vehicle), ROV DSL-120 (Remotely Operated Vehicle)},
	issn = {0148-0227},
	doi = {10.1029/2001JB000571},
	url = {http://dx.doi.org/10.1029/2001JB000571},
	author = {White, S M and Haymon, R M and Fornari, D J and Macdonald, K C and Perfit, M R}
}
