Tephra Seismites PhD student Jordanka Chaneva attended the QuakeCoRE Annual meeting in Napier between 29th August to 1st September 2022. She presented part of the on-going triaxial testing research through a poster entitled “Cyclic undrained behaviour and liquefaction resistance of pumiceous, non-plastic sandy silt”. The poster-abstract is now available to read at: http://www.quakecore.nz/wp-content/uploads/2022/08/2022-Abstract-Book-FINAL.pdf
The Tephra Seismites team at Waikato held a half-day meeting today to present progress on different aspects of the project, and discuss next steps.
Josh presented preliminary results from paleoseismic trenching and geomorphology of the Te Puninga Fault segment, Hamilton lowlands.
Richard, in his talk on ‘Soft sediment deformation structures (SSDS) in Rotoroa/Hamilton Lake’, presented observations from CT scans, grainsize analyses, and scanning electron microscope imagery of core samples.
Danche gave a talk on findings from her labwork, ‘Pumice content quantification of Tuhua tephra using different approaches’, ahead of her presentation at the QuakeCore annual meeting.
In Max’s presentation, ‘Implications of tephra thickness and grain size properties for the occurrence of soft-sediment deformation structures in lacustrine tephra layers, Hamilton lowlands’, he considered the relationship between tephra properties and the occurrence of soft sediment deformation over multiple lakes in the Hamilton Basin.
Tehnuka discussed computational analysis of core CT scans for estimating volumes of tephra layers and associated soft-sediment deformation structures.
Finally, David’s talk, ‘Origin and development of lakes in the Waikato region’, gave us an overview of different types of lakes according to their formation mechanisms and relationship with the surrounding landscape, illustrated by examples from Waikato.
At the start of June, the team met at Hamilton Gardens for a wānanga led by Wiremu Puke (Ngāti Wairere, Ngāti Porou). This began with an introduction to mātauranga Māori in geosciences research – particularly as it relates to Ngāti Wairere, as mana whenua for much of the area in which we are working. Wiremu also shared some of the history of Ngāti Wairere, and took us on a tour of Te Parapara Garden. We were lucky to have Wiremu, as one of the leaders of its planning, and construction, explain the significance of the garden design and layout, especially to the direct descendants of Ngāti Wairere, as well as visitors.
An article about Te Parapara is available on the web, and the abstract is free to read.
We have also completed CT scanning of all remaining cores from our March field campaign, with the help of Nic Ross at Hamilton Radiology. This means we can identify tephras and avoid cutting through them when we begin the next stage – opening and describing the cores. Masters student Richard Melchert has already been working on the cores from Rotoroa (Hamilton Lake). When we look at the CT scan images in more detail, they will show us the structures of any tephra seismites in 3D. We remain very grateful to Nic and Hamilton Radiology for their generous support.
Tephra Seismites PhD student Jordanka Chaneva attended two conferences in Sydney earlier this month: the International Young Geotechnical Engineers Conference (7iYGEC), and the 20th International Conference on Soil Mechanics and Geotechnical Engineering (ICSMGE). As well as presenting a paper at 7iYGEC, she participated in a victorious debate between ‘Young’ and ‘Experienced’ engineering teams on the future of geotechnical engineering!
Jordanka’s ten-minute presentation recorded for 7iYGEC describes the results of her research testing the geotechnical properties of tephra samples from local lakes. The associated paper, ‘Geotechnical properties of liquefied pumiceous layers in lakes’, is also now available to read.
The Tephra Seismites team has had a busy month, with successful field campaigns conducting ground-penetrating radar (GPR) at Rotoroa/Hamilton Lake with Dr Andrew Lorrey and John-Mark Woolley (NIWA), and sediment coring at seven Hamilton Basin lakes with Dr Marcus Vandergoes and Henry Gard (Lakes380 and GNS Science).
This follows fieldwork with Dr Pilar Villamor and Genevieve Coffey (GNS Science) in February to continue investigating Te Puninga Fault, also using GPR.
Thank you to our collaborators, and all those who helped with fieldwork permission and access.
Join the upcoming NZGS Webinar presented by Max Kluger, who will provide an overview about newest findings from the Tephra-Seismites project.
The webinar will take place on 28th March 12:30PM to 1:30PM. Registration is free an can be made at https://www.engineeringnz.org/courses-events/event/hamiltons-seismic-hazard/
While we plan for fieldwork later this summer, some of our team members have also been busy in the lab with triaxial testing to characterise the mechanical properties of pumiceous sands and tephras. These tests will tell us more about the conditions under which the tephras in our lake cores have liquefied.
In recognition of having submitted the first of our papers from the project, and a lot of hard work thus far, our group and supporters met for a special lunch last Friday (13 Aug).
Triaxial tests in the lab, led by Danche, got underway earlier this week – though these are now on hold with the latest lockdown! There is plenty to do from home, however. The team are working on abstracts for the forthcoming Geoscience Society of NZ annual conference at Massey University (Palmerston North) later this year, and on the first report to our Marsden funders. As we head into spring, we are also looking forward to resuming our fieldwork.
Our first newsletter update on research progress went out to colleagues and stakeholders this month. A copy can be found below.
Last week we also had a visit from Auckland-based team member Professor Rolando Orense for our first in-person meeting, before he gave a New Zealand Geotechnical Society presentation.