A tsunami is a series of waves generated by large displacement of water. It can be caused by a wide range of natural phenomena, creating mass movements near a large body of water; they can vary from earthquakes, to volcanic eruptions, underwater explosions, or even glacier calvings. Waves in a tsunami tend to have longer wavelengths than normal waves, and are called tidal waves. Tidal waves have significantly smaller amplitudes compared to their wavelengths, which can go up to hundreds of kilometres (Yeh et al, 1994). The tidal waves arrive to shore in what is called a ‘wave-train’ (Fradin & Brindell, 2008), whereby each wave arrives one after another, having periods ranging from minutes to hours. It is important to uncover the risks tsunamis can create for coastal areas along with the solutions possible, especially for Metro Vancouver, as it has high risks of being struck by this natural disaster. As tsunami waves acquire kinetic energy through their journey, the impact on coastal areas is the most damaging as the tidal waves have very high amounts of energy when they break on shore.

 

Following this, Metro Vancouver is situated on the circum-Pacific belt, also called Ring of Fire, which is an area with large numbers of earthquakes and volcanic eruptions in the basin of the Pacific Ocean. Many tectonic plates such as the Juan de Fuca Plate meet, and any movement from these has potential to generate a seismic tsunami that can be dangerous for Metro Vancouver, as it could inundate it. It is important to undertake this project as many megathrust events, such as the 2004 Indian Ocean earthquake, or even the Japanese earthquake in 2011 led to extreme destruction, economic damage and significant loss of life. Metro Vancouver is also prone to risks; it has a higher possibility of being hit by a tsunami, thus showing the significance of this project. Although Metro Vancouver is semi-protected by Vancouver Island and Northwestern Washington, the coastal community in the northern segment of the Cascadian subduction zone is still at a high risk of being struck by a tsunami. Many tsunamis have decreased in energy as they go around Vancouver Island; tsunami waves have been seen to decrease amplitude, from ten meters and above to only two meters or even less (Clauge et al., 2006), making it less dangerous for Metro Vancouver. However, there have also been cases of tidal waves that did not lose energy, and there is also a risk for wave amplification due to resonance (Yeh et al., 1994), which presents great danger for the Metro Vancouver coastal community.

 

The worse case scenario that is conceivable to happen in the Metro Vancouver area is a tsunami of ten meters high including the risk of resonance. This would be caused by a 9.0 magnitude earthquake, originating from the Cascadian zone, which is expected to occur in the next 50 years. The aim of this project is therefore to identify the danger zone in Metro Vancouver for all tsunami magnitudes possibilities and to find solutions for mitigation. Looking at nearest hospitals and refugee facilities and demographics this project aims to provide sensible approach to resolve the impacts of a tsunami. 

INTRODUCTION