PASSCAL Experiments http://www.passcal.nmt.edu/rss/experiments en Shale Hills Seismic http://www.passcal.nmt.edu/scheduledetails/exptnumb/201522 We plan to deploy shallow seismic surveys at the Shale Hills Critical Zone Observatory to measure both the depth to unweathered bedrock and fracture density depth profiles. We will use p-wave velocities and Vp/Vs ratios to estimate changes in porosity with depth, and relate these changes to fracture densities measured from borehole data collected at the Shale Hills CZO. We will pair these surveys with resistivity measurements at the site. RAPID: Nepal Earthquake http://www.passcal.nmt.edu/scheduledetails/exptnumb/201545 This request is for a rapid response following the Mw 7.9 earthquake of April 25, 2015 in Nepal. The goal is to deploy a 20-station network in the greater epicentral area of the mainshock to record its aftershocks. We expect to operate the network for full 6 months after its deployment is completed. This experiment will combine geodetic and seismological observations. PASSCAL data from this project will be released to the public within 1 month after the array is uninstalled. MVP http://www.passcal.nmt.edu/scheduledetails/exptnumb/201503 Deploy 6 short-period seismic stations around Makushin Volcano on Unalaska Island, AK, for approximately 12 months, as part of a newly funded EarthScope project (collaboration between UW-Madison, PI Thurber, and UC-Riverside, PI Ghosh), for seismic imaging of the volcano. RAMP1 http://www.passcal.nmt.edu/scheduledetails/exptnumb/201520 We will be completing seismic surveys over a known relay ramp in the Alvord Basin along with ground temperature surveys aimed at characterizing heat flow in active geothermal areas. TTR Surface Waves http://www.passcal.nmt.edu/scheduledetails/exptnumb/200432 We plan to analyze the dispersion curves of thumper-generated surface waves at 3 to 4 sites on the Tonapah Test Range, Nevada. Array geometry will be linear, consisting of 60 vertical sensors with 1-meter spacing. Two such arrays will be recorded at each site, oriented perpendicular to each other. Sample rate will be at or near 250 samples/sec and suitable time windows will be programmed into the requested RT-125s in the field. The terrain is mostly flat with sparse vegetation, and vehicle access is good. RAPID: Nepal Earthquake http://www.passcal.nmt.edu/scheduledetails/exptnumb/201545 This request is for a rapid response following the Mw 7.9 earthquake of April 25, 2015 in Nepal. The goal is to deploy a 20-station network in the greater epicentral area of the mainshock to record its aftershocks. We expect to operate the network for full 6 months after its deployment is completed. This experiment will combine geodetic and seismological observations. PASSCAL data from this project will be released to the public within 1 month after the array is uninstalled. Namibia http://www.passcal.nmt.edu/scheduledetails/exptnumb/201508 A ten-station BB network will be installed and operated across the northern half of Namibia for 2 years. The project is supported by De Beers. The BB sensors will be provided by Nyblade and Grand. Nyblade will also supply some RT130s. The remainder of the RT130s plus power boards and solar panels are requested from Passcal. This network will complement a 20-station network that is being installed using NARS equipment in Botswana. Mark van der Meijde from the Univ. of Twente in the Netherlands is the lead PI on that project, and Nyblade is a co-PI. The combined networks (Botswana + Namibia) will fill in a large data gap in SW Africa. Student training http://www.passcal.nmt.edu/scheduledetails/exptnumb/201528 Refraction experiment in the field behind PASSCAL. We will be using two geode multichannel units with 24 take-out cables, and also the PEG. The students will install the cables. Experiment is expected to take 2 hours. The demo will illustrate wave fields measured with the geodes and how to interfere layering underground. Crary Ice Rise http://www.passcal.nmt.edu/scheduledetails/exptnumb/201536 Our overarching goal is to understand how small-scale obstructions such as ice rises and ice rumples influence large-scale ice-shelf flow and discharge of inland ice. Here we propose to revisit CIR (Fig. 2) with new tools (radars and seismic instruments, and high-precision GPS) and make targeted geophysical measurements both on the ice rise, and where possible, across the grounding line. Our measurements, together with data collected during IGY, RIGGS, SCP, as well as new data collected recently by others from the Whillans ice plain, and satellite-derived products (patterns of thinning/thickening from ICESat, and surface velocities), will be used to validate and develop models of the evolution of grounding line dynamics of the Ross Sea Embayment. The models will be used to address the following: 1. What dynamical effect does the presence/absence of CIR have on discharge of inland ice through the Ross ice streams today? In particular, is it contributing to the observed slow-down of Whillans Ice Stream? What is its influence on Mercer and Kamb Ice Streams? 2. What caused CIR to freeze to the bed 1100 years ago? Was it a response to changes in discharge of the ice streams, or was it in response to regional relative sea-level lowering caused by glacial isostatic adjustment? How does the timing of freeze-on relate to the observations that indicate grounding-line retreat in the Ross Embayment stopped ~2000 years ago? 3. What history of ice dynamics is preserved in the radar-detected internal stratigraphy? 4. How has CIR evolved over timescales ranging from: the past 35 years since the last major field campaigns; the past millennia after the freeze-on of CIR; through the deglaciation. 5. How will CIR respond to future possible environmental changes such as sea-level rise and/or ocean warming? Will it be subsumed when the grounding line advances, or will it vanish, as occurred recently to an ice rumple when the shelf in front of Pine Island Glacier melted and thinned. Bushveld http://www.passcal.nmt.edu/scheduledetails/exptnumb/201534 This is a 3-year a NSF REU project that will involve imaging the subsurface structure of the Bushveld Complex in South Africa using passive source data. Five BB stations will be deployed, starting in the east, and each year students will retrieve data and move the stations to new locations, working towards the west. Over the 3 year period, an E-W transect of stations will have been deployed across the center of the Bushveld Complex.