Facilities

Large (1 m) direct shear apparatus

The lab operates a custom-built 1-meter biaxial deformation apparatus based on the designs of the large biaxial apparatus designed by collaborator Greg McLaskey. This apparatus consists of a steel load frame with hydraulically driven normal and shear loads. A cumulative normal load of up to 4 MN is supplied through four Enerpac RSM1000 cylinders driven by a 10000 psi hydraulic hand pump. Up to 1.5 MN of shear load is supplied through an Enerpac RSM1500 cylinder driven by a 12000 psi Vindum VP-12K dual cylinder continuous flow pump which can be driven in constant flow rate (displacement rate) or constant pressure (stressing rate) modes. The load frame can accommodate samples of up to 1.2 m fault length and is currently configured to deform sediment/gouge/powder sandwiched between 0.85 m long Poly(methyl methacrylate) (PMMA) blocks. Sample averaged shear and normal stresses are measured at the respective hydraulic cylinders via two PX359 10 kpsi pressure transducers. We have the capacity to instrument the fault/blocks with up to ten strain gauge rosettes to measure local shear stresses/strains, eight ILD1320 laseroptical displacement sensors capable of measuring up to 10 mm of slip with 1 μm resolution, and fifteen Panametrics V103 ultrasonic contact transducers, all of which can be operated simultaneously.

Active/passive ultrasonic system

We use an Elsys TraNET EPC computer for ultrasonic (active/passive) data acquisition and storage. The Elsys TraNET EPC performs the acquisition of raw, unfiltered data from 15 Panametrics p- and s-wave transducers at 0.5-50 MHz, and a 20-channel Acoustic Emission (AE) amplifier filters and boosts small signals from sensors. A TiePie HandyScope 5 200 MHz arbitrary waveform generator is configured to provide input signals for data acquisition and storage in active/controlled source mode. A National Instruments NI-cDAQ containing 12 channels for strain input and 32 differetial or 64 single-ended channels for analog voltage input, connected to the TraNET EPC, is configured to sample, record, and save strain and voltage inputs at 10 kHz.

Benchtop direct/residual shear apparatus

The lab operates an electromechanical direct/residual shear system capable of applying up to 2,500 lbf (11 kN) vertical and horizontal load capacity, and deformation rates of 6 x 10-6 to 33 mm/min (0.1 nm/s - 16.67 μm/s). Shear testing can currently be performed on 1" and 2” round samples. The apparatus is configured to record and store normal and shear loads and displacements (4 channels) with the ability to record additional sensors/channels.

Other resources

The lab also utilizes storage and computational resources at the University of Utah Center for High Performance Computing. Additionally, we have access to and frequently utilize MATLAB and Python for data analysis and post-processing, and PyLith for finite element modeling of subduction zone deformation processes.