The recent headline Scientists get offshore window on ’the big one’ is promising news for earthquake researchers at Ocean Networks Canada.
Started in 2010, the Seafloor Earthquake Array–Japan-Canada Cascadia Experiment (SeaJade) is a multiyear, two-phase collaboration involving the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), University of Victoria, Geological Survey of Canada and Woods Hole Oceanographic Institution.
During this first week of December 2013, 35 additional SeaJade seismometers will be deployed while Japanese JAMSTEC personnel and their Canadian NRCan colleagues are on board the Canadian Coast Guard Vessel John P. Tully.
Some of the scientists are returning the following weekend, just in time to fly to San Francisco for the American Geophysical Union Fall Meeting, where they’re presenting more details on SeaJade together with ONC staff scientists Martin Heesemann and Martin Scherwath, who were involved in the analysis of previously recorded data.
Exciting times ahead indeed!
Martin Scherwath comments on the next phase of this partnership to further understanding of megathrust undersea earthquakes:
“This new phase of SeaJade is very exciting for understanding what is going on at the northern Cascadia subduction zone, just off Vancouver Island.
Japanese and Canadian scientists want to record currently occurring earthquakes down to very small magnitudes and compare these with Japanese subduction zone earthquakes. The Japanese Nankai subduction zone has a relatively similar setting to Cascadia. But the big difference between Nankai and Cascadia is the number of earthquakes recorded, probably related to the very different state of the earthquake cycle in between the very large mega-thrust earthquakes that occur every several hundred years. By comparing these two subduction zones, scientists will have a more complete view of the general long-term as well as today’s earthquake and subsequent tsunami hazard.
This new phase of SeaJade comprises a very dense network of ocean bottom seismometers, deployed for the next 10 months, surrounding the NEPTUNE observatory of Ocean Networks Canada and extending all the way north across the seismically highly active Nootka fault zone.
This is following a very successful first phase of the SeaJade experiment in 2010. (see Seafloor Seismometers Monitor Northern Cascadia Earthquakes, EOS November 22, 2011)
These dense but temporary seismometer networks are able to detect earthquakes that are too small to be detected by the more broadly spaced permanent network that includes land stations as well as Ocean Networks Canada permanent cabled ocean bottom seismometers.
From a more complete seismic record with temporary dense seismic array it will be better to evaluate what is recorded with the permanent but broader seismometer network.
We’re looking forward to the recovery of the SeaJade deployment in summer 2014, after which an integrated analysis of events recorded by land-based networks, NEPTUNE, and SeaJade should greatly improve understanding of seismicity in northern Cascadia.”