McMurdo Day 69: Science Lecture

On Sunday night, the day before we flew back to Christchurch, Avi and I gave the Sunday Science Lecture.

Most Sunday and Wednesday nights, science groups will give lectures about their work to the whole station. This season, I've seen talks from the TARSAN team (studying Thwaites Glacier), the IceFin robot group (measuring the size of sub-glacial rivers), the McMurdo power plant manager (keeping the station warm), and many more. This Sunday, it was PASSCAL's turn to talk!

Avi and I (unintentionally matching) about to give our talk.

We gave an overview of a typical PASSCAL station, the work we did on Erebus this season, and the work we are planning to do on Erebus next season. I'll give a partial summary of the talk here!

What a hilarious title. Aren't we cute??

IRIS/PASSCAL is based in Socorro, NM, and we lend out seismic equipment to any NSF-funded experiment. This means we have a lot of equipment -- a whole warehouse full. So many people are needed to support this work: a Warehouse team to ship and pack out all the equipment needed for each experiment (down to the last cable), a Logistics team to make sure equipment makes it back in time and plan out when we can support experiments, a Hardware team to test equipment that comes back from the field and repair it when it's broken. And, of course, the Polar team, to support experiments in polar regions, which require extra engineering support to survive such harsh environments.

Pictures from PASSCAL's warehouse!

Avi and I are Field Engineers on the Polar team. We are field support for experiments in Antarctica in the southern-hemisphere summer and Greenland in the northern-hemisphere summer. When we aren't traveling, we work on designing stations to survive in polar regions for new experiments.

Most of our year-round polar stations follow a standard design. We have a seismometer to collect the data, a large (well-insulated) enclosure full of electronics to run the system, solar panels, and two small antennae.

Here's a typical site layout (this is our station at Lower Erebus Hut).

At the stations currently on Erebus, we have seismometers (which I've talked about before). The data collected by the seismometer travels as an analog signal through the sensor cable, where it is digitized by the datalogger. The one in the picture is an old-style, but rugged) datalogger called the Q330.

The data is stored on our huge 7-lb hard drive (which can only hold 45GB, or about 3-4 years' worth of data). A modem collects state-of-health (SOH) data on the voltages of the batteries and temperature inside the box, and transmits this data through an antenna, via the Iridium satellite network, back to PASSCAL's office in NM.

All the equipment is powered with 8x 75-lb car batteries and (in the summer) solar panels. A charge controller manages the charging of the batteries with the solar power, and has other safety features in place to cut off power to the equipment if the battery voltage drops too low.

The equipment at a standard year-round PASSCAL Polar station.

Our work on Erebus next season will involve upgrading all of the stations, as well as adding a few more. We'll replace the datalogger and hard drive with a new version that uses SD cards to store data.

We'll also add three new sensors. A broadband seismometer, which is very sensitive and can measure very small-amplitude waves to get a lot of detail. A strong motion seismometer, which measures high-amplitude waves that would otherwise "clip", or max out, the broadband sensor. And, my favorite, an infrasound sensor, which measures low-frequency (<20Hz) sound waves in the atmosphere. These are really interesting to use to study volcanoes, as they can provide information about the lava lake level in open-vent volcanoes (such as Erebus), and give more details about the amount of material released in bubbles and lava bombs.

All three sensors that we'll install at each station on Erebus next season.

The equipment we have set-up at the Castle Rock test site includes a prototype station for the Erebus work we are doing next year. This includes all three types of sensors (broadband, strong motion, and infrasound), plus another broadband sensor for reference.

The four sensors currently at PASSCAL's test site by Castle Rock.

I am super excited for the Erebus experiment next season! It's going to be a huge effort, with stations larger than any PASSCAL has deployed before.

Here are more pictures from the talk!

Me laughing with pre-talk nervousness.

Jenny, our implementer, preparing to introduce us. The guy from IT is testing the microphone.

Me talking about infrasound sensors, my babies!