I received the first watch notice by e-mail about the Indonesia tsunami on Monday afternoon (17 July) at 16:38 Singapore time (UTC +8 hours) from the U.S. National Weather Center's Pacific Tsunami Warning Centre (PTWC). I live in Singapore, and I was in my office at the time.
The tsunami watch notice said an earthquake of 7.2 magnitude on the Richter scale had occurred 20 minutes earlier at 8:19 "Zulu" (or Greenwich Mean Time), or 15:19 p.m. in Java, Waktu Indonesia Barat. Western Indonesia Standard Time is 1 hour earlier than Singapore time.
So that first watch notice was sent less than 20 minutes after the earthquake.
But it said, "a destructive widespread tsunami threat does not exist based on historical information".
Then the Japan Meteorological Agency's tsunami warning message came 10 minutes later at 16:47 Singapore time--or 15:47 (UTC +7) in Java--30 minutes after the earthquake.
As you can see in that warning message, JMA predicted that if there were a tsunami, the wave would hit the affected areas (which included coastal Java) less than 1 hour from the time of the earthquake, 30 minutes earlier.
That's not long to evacuate your home or hotel, if you have to do so. But 30 minutes is a very short time to receive and analyze earthquake information, decide what it means, and write and disseminate a message worldwide.
It's particularly quick, in my opinion, when you understand the warning is just guesswork. The analysts don't know a tsunami has been generated. NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys are supposed to do that. They monitor sea height and water pressure, but the only two DART buoys deployed to the sea floor off Java were broken and weren't working last Monday. Two reasons: they cost US$250,000 each to deploy and US$125,000 per year to maintain.
So the JMA and PTWC analysts can only guess that a tsunami might be generated, judging from the magnitude and location of the earthquake. This one occurred 10 kilometers under the ocean.
So the JMA's warning said, blandly, "there is a possibility of a destructive local tsunami in the Indian Ocean".
It didn't really sink in that those messages I received, among hundreds of others, were life-and-death information for residents and tourists on the south coast of Java.
A 2-meter (6-foot) high wave did hit less than 30 minutes later at 16:15, Java time, in Pangandaran on the island of Java, Indonesia. It killed more than 500 people and wiped out more than 60 hotels, and flattened hundreds of homes and other businesses.
Reading the reports of the destruction on Tuesday (18 July) morning, I was discouraged and somehow ashamed. I received the warning--and in time to do something--but I had no need for the information. Those who did need it didn't receive it, although there's no technical reason they couldn't have.
If you live in, work in or visit Indonesia, or any other coastal area in Asia (Thailand, Malaysia, Sri Lanka, for example) vulnerable to earthquake or tsunami activity, sign up for e-mail tsunami warnings from UNESCO's International Tsunami Information Centre (ITIC).
They're free. They seem to be remarkably accurate. E-mail, after all, is ubiquitous, even in warungs and Internet cafes in Indonesia. Not everyone in Indonesia is a fisherman or farmer.
If you have a BlackBerry or other "push" e-mail device, you'll receive the warnings wherever you are. Maybe not in coastal Java... but I wouldn't be surprised if you did. Wireless data and mobile telecom service are ubiquitous in Indonesia.
If you don't have a PDA or portable e-mail device, a public e-mail (Yahoo!, AOL, MSN) will do just fine. Do you check your e-mail occasionally when you're on vacation? I do, too. What are the chances that someone in Pangandaran was checking his or her e-mail at an Internet café on Monday afternoon at 3:30 p.m? I'd guess the chances were high, and he or she might have seen the warning message.
It's clear the JMA and PTWC ought to have RSS feeds for their messages which would automatically warn subscribers, rather than hoping those subscribers check their e-mail just after an earthquake. If they do eventually offer RSS feeds, stick their RSS feed into your RSS reader.
Don't leave home without them.
Author's Note, 28 July 2006: Senior Writer John McBeth wrote an excellent piece on the risk of a catastrophic earthquake in Java in Singapore's Straits Times on Tuesday 25 July. The story is titled "Waiting for the 'Big One'. Unhappily, the article is only available by subscription at the ST web site, but keep an eye out for it in the public domain in the future.