When we talk about the seismic danger, a Big Earthquake that affects the United States, the vast majority of people only associate it with the San Andreas Fault. However, there is an even greater danger that for hundreds of years has remained silent: the Cascadia Fault.
Centuries of tension have accumulated in the coast from northern California, United States, to southern British Columbia, Canada. Cascadia lies between the Juan de Fuca plate and the Pacific plate and has the potential to generate an earthquake of magnitude 9.0 since years of tension have accumulated along the entire fault of more than 680 miles in length. As it is impossible to know when the next earthquake will strike, seismic alerts will play a vital role in saving lives.
After the earthquake – if it is of enormous magnitude as expected – there will be a massive tsunami that would not only hit the western coast of the United States but also would travel throughout the Pacific, impacting coastal countries thousands of miles away. This already happened in Japan, in 1700, and was called the “Orphan Tsunami” since it was unknown to the Japanese people that such tsunami was caused by a great earthquake in Cascadia. Today we have the technology that will help the population to avoid disasters with notifications to alert about an upcoming earthquake.
Cascadia Tsunami, a Big Earthquake:
FEMA (Federal Emergency Management Agency) has made calculations and estimated that a total rupture of the fault would cause an earthquake, and later a tsunami, that would affect a flood area in which more than 70,000 people live, severely harming cities like Seattle, Olympia, Portland, and Salem, as well as the city of Vancouver in Canada.
FEMA has also predicted that the earthquake would seriously damage basic infrastructures such as bridges and roads, interrupting electricity and water supply in some areas for weeks or even months. In addition, more than one million people would have to leave their homes.
Such earthquake would be felt even in northern California (including the San Francisco Bay Area) but a seismic alert system could alert populations in advance, before the arrival of the destructive seismic waves.
The population is exposed to buildings that have not been designed to withstand high-intensity earthquakes (generated by great magnitude earthquakes). These buildings include hospitals, schools, police stations and fire brigades. Recently they have begun to reinforce many structures to make them seismic resistant, but it is a process that takes years, and an early warning system must complement that.
The population living in this area of the United States will have to learn how to respond to emergencies since they haven’t experienced anything similar, but above all, the inhabitants will have to be aware that this is a real and latent danger that should not be underestimated. A good first step is to have an early warning system, such as apps for the mass sending of seismic alerts for personal use.
It is important to mention that an Earthquake Early Warning is not predicting a big earthquake, but an alert system and the warning time depends on how far you are located from the epicenter.