July 2013

Posted by Ellen

The Chinese term for what's going on here gets translated as sand-washing, but the operation is really more like sand-blasting. Every summer, just before the rainy season, specialized gates in a dam holding back the Yellow River are opened wide, and the river bursts through under such high pressure that the sand and silt in the river water scour the river bottom for the next 800 km.

The nozzles will be left open for about three weeks, till the water level in the Xiaolangdi Reservoir is low enough to accommodate summer rain and the riverbed downstream has been blasted deep and clean. In its lower reaches, the Yellow River meanders slowly and is prone to silt buildup and flooding. In recent years, sand-washing has been undertaken at least once and usually twice a year.

The photo above shows the sand-washing last week; recent rains had stirred up the sediment in the water, turning it all yellow. The photo below shows the beginning of last summer's sand-washing operation, which took place after a dry spell during which the sediment had precipitated out of the water column and settled to the bottom of the reservoir.

Posted by Ellen

The top of One Liberty Place, way above the setting sun, as viewed from about 500 feet up in Two Liberty Place, a block away.

The spire of One Liberty Place is said to top out 945 feet above the ground.

Hot

Posted by Ellen

This week in Brooklyn. Could be Philly.

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House on Cypress Street near Broad in downtown Philly. 

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Above, circus clowns in their workclothes execute a wardrobe repair. Below, Allen, in workclothes from his wrestling days, hems his uniform pants.

Posted by Ellen

Looking out over Philadelphia through the window of a restaurant on the 37th floor of 2 Liberty Place, a downtown skyscraper.

Posted by Ellen

Years of drought have drastically lowered the water level of Lake Abbe, along the border between Djibouti and Ethiopia in the Horn of Africa. Vast stretches of what used to be lake bottom are now exposed, including clusters of limestone formations like these, many of which are chimneys venting sulfuric steam.

The chimneys formed when the vents were underwater; heat from the steam caused minerals to precipitate out of the lake water and build up around the rims of the vents.

Lake Abbe is a salt lake, the lowest point of a desert drainage system that has nowhere to drain. It's full of steam and sulfur because it's probably the birthplace of a new ocean, a triple junction of spreading faults where three tectonic plates are being pulled relentlessly apart from one another. Two of the faults are already so deep that they are full of ocean water: the Red Sea and the Gulf of Aden. The third fault stretches south from Lake Abbe through eastern Africa as a chain of lakes and deep depressions: the East African Rift. 

Along these faults, tectonic plates are pulling apart from one another at rates approaching an inch a year, thinning out the earth's crust in the region, and generating much volcanic activity and gaseous emissions. The geologic evidence strongly supports the likelihood that someday the land around Lake Abbe will be thousands of feet underwater, near the middle of a big blue sea.

But it will take a while. Rifting began here about 60 million years ago. At current rates of divergence, the new basin is spreading roughly 10 miles every million years. In another 100 million years, we'll have an ocean about a thousand miles across.

The drought may (or may not) be over by then.

Posted by Ellen

All we know about this photo is that it was apparently taken in Calaveras County, California, about a hundred years ago. Looks like the boys in the band were family men.

Calaveras County is a famous place in the gold-mining country of the Sierra foothills, settled in a hurry by forty-niners and immortalized (sort of) by Mark Twain in his story about competitive frog-jumping. 

Calaveras is Spanish for skulls.

Posted by Ellen

Corner store in Beijing, China.