Researchers are using Google Earth, the New York Times/IHT reports, to look for evidence of giant tsunamis, signs that the Earth has been hit by comets or asteroids more regularly, and more recently, than people thought:
This year the group started using Google Earth, a free source of satellite images, to search around the globe for chevrons, which they interpret as evidence of past giant tsunamis. Scores of such sites have turned up in Australia, Africa, Europe and the United States, including the Hudson River Valley and Long Island.
Chevrons are huge deposits of sediment that were once on the bottom of the ocean; they are as big as tower blocks and shaped like chevrons, the tip indicating the direction from which the tsunami came.
I love the idea that academics use a tool like Google Earth to — possibly — puncture one of the greatest myths of the human era: that comets only come along once every 500,000 years.
Scientists in the working group say the evidence for such impacts during the last 10,000 years, known as the Holocene epoch, is strong enough to overturn current estimates of how often the Earth suffers a violent impact on the order of a 10-megaton explosion. Instead of once in 500,000 to one million years, as astronomers now calculate, catastrophic impacts could happen every few thousand years.
There are a couple of other quirks to this story. The working group of misfits is cross-disciplinary — there’s a specialist on the structural analysis of myth in there — but only formed when they bumped into each other at a conference. How more efficient it would have been had they been blogging; they might have found each other earlier. (Perhaps they met before the blogging age; there’s a piece on the subject here from 2000.)
The second quirk for me is that the mythologist (actually Bruce Masse calls himself an enviromental archaeologist) reckons he can pinpoint the exact date of the comet which created the Burckle Crater between Madagascar and Australia using local legends:
Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. Among other evidence, he said, 14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C.
I love the idea of myths; I see them as a kind of early Internet, a way of dispersing knowledge using the most efficient tools (in those days, this meant stories and word of mouth.) We tend to think of myths as superstition and scare mongering, but in fact in many cases they are the few grains of wisdom that get passed on from generation to generation. They often get contorted in the telling, the original purpose — to warn — sometimes getting lost.
Like the Moken sea gypsies of the Andaman Sea, most of whom were spared the 2004 tsunami because they “knew from their tribal lore that this was a warning sign to flee to higher ground”, according to Reuters. On the Acehnese island of Simeulue, similar lore, dating back to the 1907 tsunami, tells islanders that “if the land is shaking and shoreline is drained abnormally, they have to go to very high land.” Only seven people out of 80,000 islanders died.
Based on this, the idea of trying to pin down the comets, the craters and the chevrons by exploring local myth makes a lot of sense. I like the idea that is being done alongside using something as modern, and as freely available, as Google Earth. I guess I’m just not happy about the implications for us current planet dwellers.
For anyone interested in helping the victims of the Yogyakarta earthquake, in which thousands of people have been killed inside their heavy stone and slate homes, here’s Indonesia Help – Earthquake and Tsunami Victims.
Sadly, this website was originally set up for the tsunami, now 17 months ago, but has been quickly resurrected to provide news and information on how to help. Even the website of the administration of the town of Bantul has updated its site with some news and photos of the quake. More information can be found at the airputih media center. The tsunami has clearly made local organisations and individuals aware of the need for rapid disbursement of information, especially on missing persons and where to give your aid. I noticed Saturday night folk walking around traffic in Jakarta with donation boxes, but we also know from experience the prevalence of scams during such times. Better to give your money to an organisation recommended by one of these sites.
More from Google Trends, the sad rise and fall in our interest in the tsunami: At the end of 2004, the Asian Tsunami piqued/peaked our attention, but the later blips (F, the last little flag on the chart, is the first anniversay) reflect, perhaps, how quickly such things are forgotten.
The Asian tsunami, and the quake near Nias, bring home how volatile the region is, particularly Indonesia. (Another quake this morning sent Nias residents fleeing into the hills in panic.) But I thought an interesting way of illustrating this volatility might be to do a sparkline of earthquakes and their magnitude around the world in the last week, highlighting those in Indonesia (most, but not only, around Sumatra) in orange:
Of course, it would be better to show their depth as well, but the sparklines tool I’m using, the excellent SparkMaker from Bissantz, is not yet up to the task. Data is from the USGS Earthquakes Hazards Program.
That’s more than 140 quakes in a week, more than half of them in Indonesia. And each one is of a size not to sneeze at, obeying, I guess the power law that, according to John Gribbin in Deep Simplicity, determines there is no single trigger for a major earthquake: An earthquake of any size is governed by the same rules. (This implies that another tsunami is not necessarily a long way off, just because there was one recently.) But if nothing else the sea of orange indicates how many Indonesians live in a state of almost permanent shock.