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Science notes / Seismology, archaeology

Slinkies simulate quakes

What walks downstairs, alone or in pairs, and illustrates the finer points of earthquakes? A Slinky.

In a video clip posted to the Smithsonian's Ocean Portal website, educator Catherine Sutera uses the time-honored American toy to demonstrate two types of seismic waves that jostled the East Coast in August's shake-up. The first is the P wave, a quickly moving compressional wave, which Sutera illustrates by stretching a Slinky out on a table and gentling nudging it, causing its springy spirals to move together and apart in a rippling motion.

But it's the S wave, or shear wave, that causes the real commotion. "These waves are a little bit slower than the P waves, but they tend to cause more of the damage that we associate with earthquakes because it moves in both an up-and-down and back-and-forth manner," she explains as she whips the Slinky in both directions.

So the next time the ground starts to heave like an off-center washing machine, hold on tight and think of it as a toy story.

-- The Washington Post

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Zekiah Fort likely found

Archaeologists in southern Maryland say they have solved a mystery that has baffled historians since at least the 1930s. They say they have found Zekiah Fort.

The fort was established in 1680 by Gov. Charles Calvert, the third Lord Baltimore, for the protection of the Piscataway people and other Maryland Indian groups that were the targets of raids by "foreign" Susquehannock and Seneca warriors from the north.

Five weeks of digging this spring and summer, led by St. Mary's College of Maryland anthropologist Julia King, have turned up Indian pottery mixed with glass trade beads, arrowheads fashioned from English brass, gun parts, a 17th century English white clay tobacco pipe and a silver belt hanger for an English sword.

The artifacts, the hilltop position, a nearby spring and rich soils to support an Indian settlement of 90 to 300 people all signaled that the search was over.

"I have no doubt this is the site of Zekiah Fort," King said.

Anne Arundel County archaeologist Al Luckenbach, who visited the site with his crew to assist in the dig, said there's little doubt about the discovery.

"I think she's found it," he said. "The location is nothing but defensive. It's hidden; it's away from the water where we normally find [Indian] sites; it's away from the road, back in the interior there, sitting on top of this hill. The only reason for being here is if you're trying to hide."

King called it "a miracle" that the site had not been developed or ripped apart as a gravel mine.

-- The Baltimore Sun