19 months ago by Weiwei Wang and Katie Woods
Our research voyage was very successful. In our two weeks out at sea we completed thirty deployments and ten recoveries. Despite being unable to work at times due to the weather, we still managed everything we could before we were due to return to Wellington.
We arrived in Wellington Harbour on the evening of the 18th October. The journey along the coast of the south of North Island was absolutely stunning.
Our voyage certainly wouldn’t have gone anywhere near as well without the R/V Tangaroa, it’s Captain Evan Solly and awesome crew. We can’t thank them enough. They were so hospitable, professional, created such an upbeat atmosphere and really were key to the success of our voyage.
It was our first voyage and we definitely worried before the trip. That’s behind us and now we can’t wait to go out again next year, hopefully!
Meeting the groups of scientists on the ship was wonderful. This was the first time we met the engineers who know everything about the instruments! We stayed with them for the whole two weeks. We talked to each other during the work frequently. We also asked questions about instruments and talked to them about the existing problems from the view of data processing. That was really an important experience to us.
During any offshore slow slip events over the next year, scientists will be both excited and nervous to know their instruments are there on the seafloor and hopefully functioning properly.
Once the instruments are recovered, the aim is to use the Bottom Pressure Recorder (BPR) and GPS-Acoustic data to determine the amount that the seafloor moves during slow slip events.
The BPRs will be used to look at the vertical movement of the seafloor while the GPS-A instruments will look at the horizontal movement of the seafloor This will require further surveying as the GPS-A instruments are not continuously recording unlike the BPRs.
The Ocean Bottom Seismometers (OBS) will be used to study slow slip event, normal earthquakes, the seismic structure of Hikurangi and will be compared with nearby drillhole measurements. The effectiveness of the cutting-edge Pressure Ocean Bottom Seismometers (POBS) instruments will be assessed as well.
No one knows what data will be recorded by the instruments we deployed until the instruments are recovered on a future voyage. For now they will stay on the seafloor, listening to the earth hum, continuously recording data for at least the next year.
The information collected will all contribute to research into understanding the earthquake and tsunami potential of the Hikurangi subduction zone. The voyage was part of a five year Ministry of Business, Innovation and Employment Endeavour funded project “Diagnosing peril posed by the Hikurangi subduction zone: New Zealand’s largest plate boundary fault.”