Ocean Networks Canada - plate tectonics

Ocean Networks Canada supports Canada’s participation in the International Ocean Discovery Program

kshoemak@uvic.ca — Tue, 09 Mar 2021 17:08:56 +0000

A new partnership between Ocean Networks Canada and the Canadian Consortium for Ocean Drilling ensures Canada’s membership in the International Ocean Discovery Program (IODP) continues until 2023, with the support and participation of 10 Canadian universities as well as Natural Resources Canada.

For over 50 years, IODP drilling expeditions have led to many fundamental breakthroughs in the understanding of our oceans, climate, and Earth evolution, including significant leaps in our understanding of plate tectonics, climate change, circulation of fluids through Earth’s crust, the limits of life on and within Earth. To date, Canadian researchers have published over 800 articles in peer-reviewed scientific journals based on data collected during IODP expeditions. The program also builds intellectual capacity through the promotion of international collaboration, education, and training, including workshops and summer schools.

Drill cores, borehole imaging, observatory data, and related geophysical imaging are obtained from beneath the ocean floor using specialized drill ships like the JOIDES Resolution pictured above. (Photo: William Crawford, IODP/TAMU)

One of ONC’s deep-sea networks extends across the Juan de Fuca Plate, which has been a hot-spot of scientific ocean drilling since 1991. Several of the boreholes drilled in the Northeast Pacific are equipped with CORKs (Circulation Obviation Retrofit Kit) hydrologic observatories that enable geoscientists to observe changes in subsurface pressures and temperatures caused by earthquakes, storms, hydrothermal convection, and regional tectonic plate strain.

Ocean Networks Canada provides live connections to CORKs at Cascadia Basin and Clayoquot Slope, with future demonstrations planned using the CORK at Cascadia Basin to monitor the safe injection and mineralization of CO2 into sub-seafloor basalt as a future negative emissions solution to climate change.

John Jamieson, the Chair of the Canadian Consortium for Ocean Drilling, is a member of Ocean Networks Canada’s Ocean Observatory Council. He holds a Canada Research Chair in Marine Geology at Memorial University of Newfoundland. (Photo: William Crawford, IODP/TAMU)

For more information on the Canadian Consortium for Ocean Drilling, and IODP can be found at www.iodpcanada.ca.

Tsunami alert follows 8.2 quake off Chile

dwowens@uvic.ca — Wed, 02 Apr 2014 04:25:42 +0000

On April 1 at 4:46:45 PM Pacific Daylight Time (23:46:45 UTC), a magnitude 8.2 earthquake occurred off Chile's Pacific coastline, according to the US Geological Survey. Ocean Networks Canada instrumenatation captured both ground shaking and a very small tsunami as they crossed the northeast Pacific.

Map of the epicentre and 16 aftershocks along the subduction zone between the Nazsca and South American plates, 1 April 2014. Data provided by USGS and plotted using Google Earth. (Click to enlarge.)

At a depth of 20.0 km below the seabed, the shallow near-field quake struck 86 km northwest of the mining area of Iquique, hitting a region that has been rocked by numerous quakes over the past two weeks. According to the USGS, this earthquake occurred as the result of thrust faulting at shallow depths near the Chilean coast. The location and mechanism of the earthquake are consistent with slip on the primary plate boundary interface, or megathrust, between the Nazca and South America plates. In this area, the Nazca plate subducts eastward beneath the South America plate at a rate of 65 mm/yr. Subduction along the Peru-Chile Trench to the west of Chile has generated the uplift of the Andes mountain range.

Ocean Networks Canada's seismometer in Cascadia Basin recorded the tremors as they crossed the North Pacific. Seismic data clearly indicate arrival of the initial P waves approximately 750 seconds (12.5 minutes) after the earthquake, and following S waves about 1375 seconds (23 minutes) after the earthquake struck. Bottom Pressure Recorders on the NEPTUNE Observatory also detected passage of the tsunami in real time, as it crosses our observing stations in the northeast Pacific.

Data from the Cascadia Basin ocean-bottom seismometer indicating arrival of P and S waves. The top trace shows East-West motions, the centre trace shows North-South motions, and the lower trace shows vertical motions. (Click to enlarge.)

A 1.9-metre tsunami was recorded at a northern Chilean port Tuesday evening. The Pacific Tsunami Warning Center issued an alert for all of Latin America's Pacific coast. There was no threat issued to the Pacific coast along North America.

NOAA issued a forecast of tsunami heights as the energy propagated away from the source region, indicating heights up to 100 cm close to the epicenter, with rays of 2-10 cm wave heights extending across portions of the South Pacific Ocean toward New Zealand and archipelegos in the South-Central Pacific.

Tsunami wave energy propagation forecast issued by the Pacific Tsunami Warning Center, showing contours of maximum wave amplitudes (in cm) associated with the 1 April 2014 earthquake.

Travel times for tsunami propagation were also modeled by the National Tsunami Warning Center, with expected arrival of a small (2-4 cm) tsunami in coastal British Columbia beginning 15 hours after the event, around 7:00 AM Pacific Daylight Time.

Predicted travel times for tsunami waves generated by the 1 April 2014 earthquake. Three-hour intervals are marked by the heavy white lines, intermediary hours are marked by blue shades and dashed white lines indicate half-hour boundaries. Arrival in both New Zealand and British Columbia was predicted to begin approximately 15 hours after the initial earthquake.

Seafloor pressure traces from the CORK pressure instrument at Cascadia Basin, 1-2 April 2014. The upper plot shows initial passage of the earthquake just past 00 UTC (indicated by the blue lines), followed by passage of the small tsunami beginning at 14 UTC. The lower plot focuses on the tsunami onset period, 11-15:20 UTC. Wave amplitudes at this deep-water site (2660 m) were approximately 8 mm.

No stranger to seismic activity, Chile is one of the world¹s most earthquake-pronecountries. In 2010, a magnitude-8.8 quake and ensuing tsunami in central Chile killed more than 500 people and destroyed several hundred thousand homes along the coast.

Endeavour's Complex Environment

dwowens@uvic.ca — Wed, 19 Jun 2013 07:00:00 +0000

The Endeavour segment of the Juan de Fuca ridge is home to one of the deepest (2200 – 2400 m) collections of experiments in the NEPTUNE Observatory. This deep-sea mountain ridge is located approximately 300 km off the British Columbian coast along the spreading crustal boundary between the Juan de Fuca and Pacific tectonic plates. The Endeavour site presents an elaborate network of seafloor structures where active hydro-geothermal venting creates highly variable local temperatures throughout the system. Due to its dynamic characteristics, Endeavour offers a rare opportunity to study globally significant chemical, biological and geological processes unique to these otherworldly deep-sea environments.

Hydrothermal Vents and Habitats

Located on mid-ocean ridges, hydrothermal vent ecosystems are characterized by extreme environments and unique organisms, which don’t depend on sunlight. Photosynthesis is the way plants usually convert energy to food, but deep-sea hydrothermal vent communities are sustained by a special group of microorganisms, which carry out a process known as chemosynthesis. This allows the bacteria and archaea to produce organic matter for themselves and larger animals using energy from chemical reactions that occur as superheated mineral-laden hydrothermal fluids mix with seawater. Many of the species found here are endemic to these extreme deep-ocean environments. Several studies have shown that the distribution and composition of vent communities are strongly influenced by local geological, physical and chemical processes. We know very little about the day-to-day life of hydrothermal vent organisms or how these particular ecosystems evolve over time.

Ongoing Research

Endeavour has been the site of intensive investigation for more than 20 years and was officially preserved as the Endeavour Marine Protected Area (MPA) in March 2003.
Endeavour Node is the hub for a dynamic network of instruments deployed at several Endeavour hydrothermal vent fields: Main Endeavour Field in the centre, Mothra to the south, High Rise and Salty Dawg to the north.

Within these fields, hydrothermal vent edifices with their sulfide towers and black smoker chimneys are given fanciful names like Hulk, Crypto, Dante, Grotto, Godzilla and Faulty Towers. Four instrumented moorings mark the corners of a rectangular box around the vent fields, with mooring arrays positioned to the northwest, northeast, southwest and southwest.

Some of the instruments deployed at Endeavour relay a constant stream of real-time data monitoring heat flux dynamics, dissolved minerals, current flow, micro and macro-organism behavior and population, and seismic activity.

Ocean Networks Canada - plate tectonics

Ocean Networks Canada supports Canada’s participation in the International Ocean Discovery Program

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Tsunami alert follows 8.2 quake off Chile

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Endeavour's Complex Environment

Hydrothermal Vents and Habitats

Ongoing Research

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