Making ‘Wave’fields with IRIS

By Isaac Woelfel

In May, I received an email about an IRIS (Incorporated Research Institutions for Seismology) Research Wavefields Demonstration Community Experiment that was going to be conducted in Northern Oklahoma in the summer.

Sounds like it’s going to be hot, I thought.

Flash forward to Monday, June 20th with a high of 97 degrees and 50% humidity. I found myself on a team that would deploy cutting-edge, three component 5 kHz nodal-type sensors. The sensors, which are about the size of a paint can, house onboard GPS-timing and can run independently for up to 30 days collecting seismic data.

The hot and humid week near Enid, Oklahoma was an incredible hands-on educational experience in deploying next-generation seismic equipment along with the chance to work alongside other students, postdocs, and faculty from all over the world to collect a full wavefield dataset.

The following photos and commentary further document my part in the IRIS Research Wavefields Demonstration Community Experiment and the deployment of 75+ nodal sensors over four days with my road deployment team.

Picture1

 

 

The three component 5 kHz nodal-type sensors. The sensors, which are about the size of a paint can, house onboard GPS timing and once deployed, run independently for up to 30 days collecting seismic data. Attached to the top of the sensor is the HHT (hand-held terminal) which shows the order the sensors are to be deployed as well as activates the GPS on the sensor to receive location-precise data.  The sensor is then buried about a foot underground.

 

 

Picture2

 

 

 

STEP 1: Rhiannon Vieceli, Geophysics student from Penn State, uses a pick-ax to break up the soil, easing the strain of digging in the hard clay—making up most of the soil where our team was deploying sensors.

Picture3

 

 

 

 

 

 

 

STEP 2: Once the soil is broken up with the pick-ax, a hole that the sensor will be placed into is dug. Alexander Besov, Research Assistant at The University of Oklahoma, digging the hole for the sensor.

 

 

 

 

When the hole is complete, even though the sensor is equipped with a spike on the bottom, a foot long piece of rebar is pre-driven where the spike will go. The sensor is too sensitive to be driven into the soil by hammering it into the ground.

Picture4

 

 

 

 

 

Step 3: Jonathon Schmidt, Research Assistant at New Mexico Tech, takes a hammer to a foot long piece of rebar to pre-drive where the stake from the sensor will go.

 

 

 

Picture5

 

 

 

Step 4: Rhiannon Vieceli recording vital information, such as the sensor serial number, as well as making notes about the terrain and other points of interest near the location that the sensor is being placed. Hanging from her hand is the three component 5 kHz nodal-type sensor that will be buried.

 

 

 

 

Picture6

 

 

Step 5: Emily Morton, Research Assistant at New Mexico Institute of Mining and Technology, places the sensor in the hole. Her next steps will be to orient the sensor to the north using a compass as well as ensuring that it is level with a bubble level.

 

 

 

 

 

Picture7

 

 

 

Step 6: Once the sensor is both oriented north and leveled, Rio Sophia Diniakos, Research Assistant at New Mexico Institute of Mining and Technology, ensures the order of the sensor deployment and activates the GPS via the HHT.

 

 

 

 

 

After the GPS is activated, the sensor is buried and the team moves on to repeat the process at the next location. Only 74 more to go!

It was a hot and tough week to work in Oklahoma, but the IRIS Research Wavefields Demonstration Community Experiment was a very positive and educational experience with the opportunity to work alongside other great professionals in the field. I am looking forward to what the data yields as a result of all of our hard work!

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