California is earthquake country and is located within “The Ring of Fire, a horseshoe-shaped, 40,000 km-long string of seismically active zones and volcanoes around the Pacific Ocean. Almost 90% of all the earthquakes in the world occur along the Ring of Fire, and 75% of all of the Earth’s active volcanoes lie along the Ring.

Caused by the movement of tectonic plates, giant slabs of the Earth’s crust, earthquakes along The Ring of Fire occur as these plates collide and either strike each other or one moves above or under the other. These collisions not only cause earthquakes, they also create mountain ranges, and because hot magma from the Earth’s core can escape along these ‘seams’ in the Earths crust volcanoes grow and erupt.

The M 7.8 1906 earthquake along the San Andreas Fault was caused by just such a collision and killed an estimated 4,000 people. But 17 years later another earthquake along The Ring of Fire caused approximately 140,000 deaths when a M 7.9 earthquake, known as the Great Kantō, struck Japan, devastating Tokyo and Yokohoma. As was the case in 1906 in California, the Great Kantō earthquake was followed by fires that caused further destruction. But in Japan they experienced a massive tsunami as well, one that reached almost 40 feet high in places.

Today Tokyo and Japan have some of the strongest seismic building codes in the world, and since October 2007 Japan has had a national earthquake early warning (EEW) system. Japan has a culture of preparedness; every year on September 1st, the anniversary of the 1923 Great Kantō earthquake, Japan observes National Preparedness Day. In reflecting on this national approach to preparedness, UN Secretary General Ban Ki-moon held up Japan’s disaster preparedness efforts as a model to the world, saying in 2016 that, “…the rest of the world has much to learn from Japan, if we are to make progress on saving lives and livelihoods, and reducing disaster losses.”

In our next Post we will learn more about Japan’s preparedness.