A Simple Relation to Constrain Groundwater Models Using Surface Deformation.

A simple relation between pore pressure change and one-dimensional surface deformation is presented. The relation is for pore pressure change in a confined aquifer that causes surface deformation. It can be applied to groundwater models of any discretization and is computationally efficient.

Slow slip source characterized by lithological and geometric heterogeneity.

Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) of well-documented SSEs at the Hikurangi subduction zone offshore New Zealand offers a unique opportunity to link geophysical imaging of the subduction zone with direct access to incoming material that represents the megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this incoming material before it is entrained immediately down-dip along the shallow plate interface.

Conduit properties and karstification in the unconfined Floridan aquifer.

Exchange of water between conduits and matrix is an important control on regional chemical compositions, karstification, and quality of ground water resources in karst aquifers. A sinking stream (Santa Fe River Sink) and its resurgence (River Rise) in the unconfined portion of the Floridan Aquifer provide the opportunity to monitor conduit inflow and outflow. The use of temperature as a tracer allows determination of residence times and velocities through the conduit system.