Subduction zones are described as the movement of the earth’s plates. When these collide the cold crust sinks and the other plate overlaps on top of it. For Geologists this simplified explanation is not enough; they suspect that the plates become locked together and later on after centuries spring back and create an earthquake.
The Pacific Northwest Cascadia fault is a subduction zone fault that stretches from mid-Vancouver Island to Northern California, capable of producing a 9 magnitude earthquake. This puts a number of States in danger since it causes a tsunami and at present no instrument is measuring its strain. The past shows that Cascadia’s last big event in 1700 was very similar to the March 2011 Japanese earthquake including a tsunami that travelled across the Pacific. This is proof that what is recorded onshore is not indicative of what is happening offshore hence the need of underwater sensors. In fact researchers started to install these sensors to find out more about the faults and get some information prior the hitting of an earthquake. However in March 2011, whilst ship KAIYO was installing the underwater seismic observations, an earthquake broke out in a different fault causing a lot of problems to the communities living on the coast. No one had thought that the Tohoku coast could generate such earthquakes. Part of the reason for this, is the lack of devices that could help in predicting these phenomena and diminishing some of the related disasters. However at present Japan has 50 observatories offshore compared to the 8,700 on land.
Susan Avery, WHOI president and director expects that real time data flowing from the fault will become more accurate to aid emergency response more readily. Hole, McGuire and Collins will work on installing tiltmeters at approximately 4 kilometres above the Cascadia subduction zone thrust interface. This will be located in a 300 metre deep borehole and will use an existing seafloor cable infrastructure, NEPTUNE Canada, enabling immediate access to data. The tiltmeter at Cascadia subduction should be up and running by summer 2013. According to McGuire this instrument will allow scientists to collaborate across disciplines as well as provide interesting borehole signals.
References:
http://www.nature.com/news/2011/110824/full/476391a.html
http://www.hydro-international.com/news/id5319-First_RealTime_Seafloor_Earthquake_Observatory.html
