We know that Vancouver will have a large mega earthquake because researchers who have been able to use sediment samples taken off the coast of Vancouver island to reveal the pacific coasts seismic history. The region stretches from the north tip of Vancouver island to northern California has experienced 22 major earth quakes over the last 11000 years and is due for another. The span between major thrust earthquakes is 300 years. The last major earth quake was 313 years ago. Researchers extracted a sediment core from the sea floor of Effing ham inlet in Barkley Sound on the west coast of Vancouver island, and used radio carbon dating to determine when mega thrust earthquakes occurred in what is known as the Cascadia subduction zone. The sediments preserved on the bottom of Effing ham inlet resemble rings of a tree each year a thin layer of sediment. These layers show what has happened in effing ham inlet year by year back all the way to the end of the last glaciations about 11 000 years ago. Japanese written records confirm a 8-9 magnitude earthquake along the north american coast at 9 pm January 26 1700.
Metro Vancouver geological settings
The metro Vancouver region of south western B.C lies at the fore front of the north american plate. on the western edge of the north american plate, The Juan de fuca plate is subducting beneath and slowly deforming the continent. The dynamic geological settings make the densely populated region susceptible to frequent seismic activity and increase the risk of dangerous mega thrust earthquakes. The metro Vancouver region is surrounded by the mountains and the pacific ocean making it very isolated and vulnerable in the event of a large earthquake.
Liquefaction
During an earthquake shaking can cause loosely packed water saturated sediments such as sand or silt turn into a fluid mass, this is known as liquefaction. When this happens the sediments loose their strength and can no longer fully support structures, which may lean, sink or settle. All new structures in Richmond are built on denser or improved ground and use foundation systems such as piles raft slabs that are specially designed to lower the risk of liquefaction. Richmond's soil is made of silt and sand. The energy caused by an earthquake could take longer to dissipate and the shaking more intense in these softer soils then it would be on firmer soil and bedrock. The good thing is that softer soils tend to absorb the damaging high frequency shaking better then areas located on rock. Richmond is an island. Richmond is connected to other communities through a network of bridges. Seismic upgrades to a number of older bridges have been under taken in recent years and continue to enhance their strength. This will help to alleviate transportation impacts in the event of an earthquake.
Tsunami
Experts studying the second largest earthquake measured in Canadian history have zeroed in in on the pacific archipelago of Haida Gwaii as the likely source of a future large earthquake and tsunami. What this has done is raise the possibility of future thrust earthquakes and tsunamis along this part of the British Columbia margin. An earthquake off B.C's coast relived some of the regions tectonic strain, but new research shows the sifting also increased pressure immediately south of the islands along the Queen Charlotte fault. Vancouver island will be the most impacted by the tsunami because it will be the first land mass the tsunami will hit.
Flooding and Landslides
A earthquake scenario researchers have done is what would happen if the sea level were to rise by four meters. The inter web they used showed that Vancouver would survive just fine but the suburbs of Richmond, Delta and Lander would be completely submerged underwater. Stevenson, Richmond's touristy fishing village, would be completely wiped out and much of Delta and Lander's agriculture would be flooded. Surrey and Langley would also see flooding in certain areas. Metro Vancouver is at risk of a tsunami. Studies show that sea levels in Vancouver could rise by as much as one meter by 2100. Vancouver island is covered in mountains and seismic activity from the Juan De Fuca and explorer plates, over steep cliffs and high rain fall make Vancouver island susceptible to land slides. Land slides can block roads for days to weeks and could cut power and even kill people.
Infrastructure
New research shows that Vancouver would rock harder and longer from an earthquake then any other areas given the shape and composition Vancouver is on. Studies show that seismic waves would intensify when they pass through the Georgia basin, the deposit of softer sedimentary rock that lies partly beneath metro Vancouver. These studies make the officials check the readiness of infrastructure in the region. The increase of intensity would make the ground shake three times harder then it would be in a different region. Damage to well designed buildings in the area would be inevitable in an earthquake of that intensity, while older structures like the brick buildings in Gas Town would be hit hard. Researchers say that the findings will help with seismologists determine where to place more instruments to record further earthquakes. These findings can also be used to upgrade codes for buildings, bridges and other infrastructure to make then more secure.
Preparation
Metro Vancouver takes many steps to make sure that people are prepared. Children in school are taught to hid under heavy tables or desks or in hallways. People should also hide in corners of rooms and archways. There are courses that are offered to teach CPR and first aid. There is also earthquake insurance. Families are encouraged to practice earthquake evacuation and make or buy earthquake kits. The purpose of an earthquake kit and other preparations is to survive without help for at least 72 hours.
Economics
Some statistics say that Canada is not prepared for a possible 9 magnitude earthquake and would cost around 60 to 75 billion in damage. It will have a domino effect on the entire Canadian economy. It is estimated that 62 billion will be from direct damage and 12.7 billion in indirect impact caused by things like supply chain interuption and infrastructure damage.
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