Presentation is loading. Please wait.

Presentation is loading. Please wait.

Science on the Leading Edge: Plate tectonics on Canada’s West Coast

Similar presentations

Presentation on theme: "Science on the Leading Edge: Plate tectonics on Canada’s West Coast"— Presentation transcript:

1 Science on the Leading Edge: Plate tectonics on Canada’s West Coast
The Bamfield Marine Sciences Centre is located on the outer edge of Vancouver Island’s west coast. The Public Education Program works with teachers and students to promote science learning with a focus on the ocean and connections to the ocean. Bamfield Marine Sciences Centre, Public Education Program Teachers Workshop, October 24, 2008 Pacific Geosciences Centre

2 Thanks to Kim Juniper (for the idea)
Western Canadian Universities Marine Sciences Society Bamfield Marine Sciences Centre Natural Sciences and Engineering Research Council (NSERC) PromoScience (Funding) EdGeo (funding for teachers workshop, we hope) NRCAN Geological Survey of Canada, Pacific Geosciences Centre, (Jane Wynne, Mike Schmidt in particular) University of Victoria NEPTUNE Canada UNAVCO All the pilot teachers and students from Calgary Science School, Robert Bateman Sec., Summerland Sec., St. Michaels Univ. School, Mark Islfeld Sec., Crestwood School And many others… Thanks go out to all the groups and individuals who made the SOLE learning material available for teachers and students.

3 Objectives Link plate tectonics to British Columbia’s current geologic situation Visualize the movement of local tectonic plates Make connections between plate movement, sub-sea ridges, divergence, subduction, earthquakes, tsunamis and volcanoes Use real-time data to plot the movement of GPS stations at Victoria and Seattle

4 Where in the world is the Juan de Fuca plate?
Tectonic Plates The Earths crust is made up of tectonic plates that slowly move on currents of molten rock or magma. Continental plates are less dense and tend to float over dense metal laden oceanic plates. Where in the world is the Juan de Fuca plate? Hint: it is very small.

5 ‘Creation and destruction’ of plates.
Divergence: two plates moving away from each other Subduction: a dense, heavy oceanic plate “slides” under a lighter continental plate

6 Seafloor Spreading Magma rises to the seafloor through a series of fractures Cools, then sticks to walls forming vertical sheets Ocean crust spreads in both directions away from the ridge University of Washington & NOAA

7 Juan de Fuca ridge, underwater volcanoes.
Juan de Fuca Ridge: Deep Sea Vent

8 Volcanoes Volcanoes lie above the deep subducting crust which is hot enough to melt the mantle above Hot, buoyant magma rises up to erupt at the surface Image: Google Earth

9 Juan de Fuca Plate

10 Block diagram of Southwest B.C., showing features.
Sub-sea ridge, divergence, Pacific Plate (dense), Juan de Fuca Plate (dense), spreading at ridge, size of Earth not increasing, North American Plate (more buoyant), movement, subduction zone, brittle part sticky, melting part, volcanoes, (use lasagna analogy) Turner, R. J. W., Clague, J. J., Groulx, B. J.,1998: Geoscape Vancouver, living with our geological landscape; Geological Survey of Canada, Open File 3309

11 Earthquakes Southwestern British Columbia Earthquakes in the last 30 days (from

12 Not all months are created equally.
Earthquakes Aug 14 - Sept 13

13 There’s a whole lot of shaking going on.
Five years worth of shaking.

14 Vancouver Island Earthquakes
Epicenters are located along plate margins and above subduction zones (faults) Earthquakes are mostly magnitude 2-4 on the Richter scale Eg. magnitude 3 would move the ground about one millimetre The Cascadia Subduction fault is locked at a depth of 20km – brittle rock and rock above are being flexed Eventually a slip will occur causing another large earthquake

15 wood-block print, the Great Wave off the Coast of Kanagawa,
Tsunami, Adapted from a wood-block print, the Great Wave off the Coast of Kanagawa, by Hokusai. The December 2004, Sumatra, Indonesian Islands earthquake rupture area is similar in size to the Cascadia subduction zone. The last megathrust earthquake here was in January The tsunami from that quake was devastating to coastal communities here and in Japan. Mt. St. Helens, USGS

16 The great 1700 Earthquake This mathematical model of the January 26, 1700 megathrust earthquake shows the wave as it reaches Hawaii. .

17 Is there evidence the plates are actually moving?
Data collected by a network of GPS (Global Positioning System) receivers track the exact position of nodes Compare moving GPS nodes to stationary nodes further inland Measure how far and in which direction the crust is deforming We will have a look at the data and graph the location vectors The Geological Survey of Canada runs the permanent GPS tracker network that investigates crustal deformation in British Columbia. It is called the Western Canada Deformation Array and it produces measurements for Canadian and International scientists.

18 Western Canada Deformation Array (WCDA)
Permanent GPS Tracker Network Geological Survey of Canada Measures plate deformation in the Cascadia Subducation Zone Seismic hazard in densely populated region of British Columbia

19 GPS technology used to measure continental crust movement.
Latitude (north/south) Longitude (east/west) Elevation

20 Movement of Victoria GPS Station (East-West) and Correlation with Tremor Activity

21 What the data looks like.
Download as a .csv file, save as an Excel file, use Excel to graph and calculate regression line and slope Use the slope of the line (mm/day) to calculate average yearly movement The UNAVCO web-site (Outreach & Education) has current data that can be down-loaded so that the class is working with near real-time data

22 Remember, when looking at graphs:
Check the axes and the units Look for trends The slope of line is simply rise/run (or change in y over change in x) Let’s look at some near real-time GPS data from Victoria & Seattle

23 We are going to plot vectors for Victoria and Seattle GPS nodes
You have a data table with four boxes Victoria eastward is already calculated Use the slope (mm/day) X days/year to calculate average annual velocity Example:

24 Y= x Slope = mm/day

25 Y = x Slope = ____ mm/day

26 Y = x Slope = _____ mm/day

27 This is the last graph for this exercise. What is missing?
Seattle north Y = x What is the slope of the line?

28 How to plot a vector. Start at zero Mark how far east and and how far north Make a point Draw a line from 0 to the point Put an arrowhead on the point North Point West East Congratulations! You made a vector that shows magnitude and direction of movement. South Now, draw the Victoria & Seattle vectors

29 Discussion Compare the vectors
Why do Ucluelet and Neah Bay vectors have so much more velocity? Predict the vertical movement at Ucluelet and Neah Bay vs more Eastern nodes? What are some sources of error?

30 What’s next? Extending the network to the seafloor.
NEPTUNE Canada will provide real-time data on seismic activity to shore via a powered fiber-optic cable. Cabled-laying system on ROPOS ROPOS Canada copyright

Download ppt "Science on the Leading Edge: Plate tectonics on Canada’s West Coast"

Similar presentations

Ads by Google