Thursday, June 2, 2011

Big Wave, Big Picture

Beneath the surface of tsunamis’ past, present and future

Yellowstone National Park’s “supervolcano” is 20,000 years past due for a major eruption, at least that’s what alarmists will say. In 2003, a 4.4 magnitude earthquake occurred just nine miles southeast of the entrance to the park, and Marshall Masters, publisher for [], a science-fiction based website, speculates, “Simply put, anyone living within 600 miles of Yellowstone could be sitting in a modern-day Pompeii.”

So what do these crazy theories have to do with us?

According to tsunami experts, once a huge volcano starts exploding, magma is pushed quickly into the geologic “plumbing” system lying underneath. In coastal areas, like Hawaii, this can produce huge tsunamis.

Take for example the catastrophic tsunami of December 2004, when the fourth most powerful undersea earthquake in history killed 230,000 people in Sumatra, Indonesia. The earthquake unleashed a tsunami so powerful that it moved the entire island 100 feet to the southwest. And most recently, after a 9.0 earthquake crippled Japan’s Fukushima Daiichi nuclear plant this year, a tsunami hit Sendai 25 minutes later. More than 27,500 people were left dead or missing three weeks after the quake.

What We’ve Learned…so far

Shortly after the recent Japanese tsunami, Kwok Fai Cheung, a professor at UH–Manoa’s Department of Ocean and Resources Engineering updated inundation maps provided to the county civil defense agencies as a “worst case scenario” for Hawaii’s next tsunami. The study is based on the largest Pacific-based tsunamis that have occurred during the last century, and on studies from earthquake hotspots throughout the Islands. Cheung’s research is also based on maps of five historic earthquakes that led to five deadly tsunamis in Kamchatka Peninsula, the Aleutian Islands, Alaska and Chile.

In 1989, Hawaii was the first state to devise official tsunami evacuation zones, according to George Curtis, a Hawaii County tsunami advisor and semi-retired UH-Manoa professor. “If you are in an evacuation zone, you move out, and you are safe,” Curtis says. “It doesn’t matter where [a person] moves, as long as they get out of the evacuation zone.”

Evacuation zones are based on predicted maximum inundation levels for any tsunami from any direction, and include traffic and population patterns “We draw up those inundation limits on maps, and then it’s up to the county to develop an evacuation zone that would be mauka of that,” Curtis says, ”These zones can be found in the local phone book. County civil defense agencies are in charge of drafting them, and each county is responsible for drawing up their own.” More >>>

Location: Cayman Islands