Date/Time
Date(s) - Thu 17 August
12:00 - 13:00
Location
CO304, Cotton Building, VUW
A controversial, yet tantalizing recent theory suggests that global rising sea levels can cause an increase in the frequency of volcanic eruptions and earthquakes. Such connectivity between the atmosphere, hydrosphere, and geosphere at 1000-1,000,000-year time scales however is difficult to prove, due to a lack of well-dated, well-preserved, long sediment records. Co-located volcanic eruptions in the TaupōVolcanic Zone and earthquakes associated with the Hikurangi Subduction Margin, coupled with new long (>900 m) sediment marine records over multiple glacial-interglacial cycles, make Aotearoa-New Zealand’s, North Island, plate boundary an ideal location to constrain these processes.
During this talk, Lorna will highlight some the work that she and her team of 20 international and national researchers are doing to answer this question, as part of a fully funded Royal Society, Marsden project. The project uses International Ocean Discovery Program (IODP), Expedition 375 sediment cores extracted from more than 3km water depth within the Hikurangi Trough to focus on understanding the connections between glacio-climatic change, volcanism, and earthquakes over the last ~2 million years. The team have unravelled details of past seafloor processes that are closely coupled to changes in climate and ocean conditions. During the last glacial maximum for example, about 20,000 year ago, there was a sixfold increase in the delivery of sediment to the deep ocean, with unprecedented values of 1 m of sediment accumulation every 100 years.
Today these systems are choked with sediment, as they are shed off an uplifting and occasionally explosive landmass. It is almost incomprehensible to imagine the magnitude and ferocity of natural physical and biogenic processes in the past.
Zoom link : https://vuw.zoom.us/j/97963373089