Stephanie Tickle
Contact
Email: stephanie.tickle@vuw.ac.nz
Office: CO418
Qualifications
BSc in Geology, Victoria University of Wellington (2018)
MSc in Geology, Victoria University of Wellington (2021)
PhD Candidate in Geology
Research Interests
Paleoseismology, Sedimentology
PhD thesis
Title
Testing the Assumptions of Turbidite Paleoseismology using the 2016 Kaikōura Earthquake.
Supervisors
- Dr Alan Orpin (NIWA)
Project objectives and description
Turbidite paleoseismology allows for greater insight into the history of large earthquakes along subduction zones, however, as earthquakes are not the only possible trigger of turbidity currents, it relies heavily on accurately establishing synchronicity of turbidite deposition across a wide area. One method used to identify synchronous deposition is the confluence test, which counts the number of turbidites above and below a confluence, and if the number below the confluence is the same as in the tributaries above, the turbidites were triggered simultaneously. However, some have proposed that complexities in sediment routing could jeopardise the confluence test, while others suggest the positioning of cores above canyon thalwegs could provide variation in the number of turbidites, making counts inaccurate. Another method, termed “turbidite fingerprinting” utilizes the physical and geochemical characteristics of turbidites to correlate deposits, though these may show variability between individual canyons, complicating the “fingerprint” signal. The ability to correlate turbidites across a wide area is paramount to the success of turbidite paleoseismology, thus, it is important that the methods used to do so are robust.
The 2016 Mw 7.8 Kaikōura earthquake triggered turbidity currents in ten consecutive canyons across the southern Hikurangi margin, providing an opportunity to examine known earthquake-triggered turbidites in nature, and test some of the methods by which synchronicity of turbidite deposition has been established in the geological record. My research will examine how an earthquake-triggered turbidite has been deposited, and determine how vital core positioning is to a turbidite paleoseismology study. Additionally, both the confluence test and turbidite fingerprinting will be examined for the Kaikōura turbidite and a penultimate turbidite to determine how well these event deposits can be correlated.