June 29, 2009—Sinkholes around the Dead Sea pose a hazard to tourists and the environment alike. The danger may only get worse, and geologists hope to map problem areas to help protect the public.
© 2009 National Geographic (AP)
The Dead Sea is the lowest point on earth, and runs more than 50 miles in length, and stretches 11 miles across at its widest points, bordering Israel, the West Bank, and Jordan.
Large sections of the coast are fenced off and signposted in Hebrew and English: warning of sinkholes.
The seas dropping water level is leading to dangerous consequences.
In April, an Israeli hiker wandered into an area that had no warning signs and was critically injured when he fell into a sinkhole.
SOUNDBITE(English) Eli Raz, Geologist: "Due to the rapid drop, the ground water are now facing with the salt rock and the salt rock is undergoing a very rapid dissolution. Cavities are formed inside and eventually the surface collapse down to the cavities and these are the sinkholes."
Geologist Eli Raz himself became the victim of a sinkhole several years ago.
SOUNDBITE (English) Eli Raz, Geologist: "I just remember that I was busy by documenting a new sinkhole and then suddenly I found myself covered by a pile of avalanche on the bottom of a sinkhole."
He spent 14 hours at the bottom before his rescue, and even wrote his will, not knowing he would be saved.
SOUNDBITE (English) Eli Raz, Geologist: "I just can tell you that it was terrible, very frightened and in the first place, in the beginning, I started to write my will, without knowing that somebody will find it of course."
Now Raz is working to save others from a similar fate, leading an effort to map the sinkholes that are spreading on the banks of the saltwater lake.
The formation of the dead sea sinkholes are caused by a drop in the seas water level due to limited rainfall, the diversion of much needed water from its upstream sources, pollution, and industrial evaporation of water by the Dead Sea mineral industry.
As the sea levels drop, high levels of salt are left behind in the soil.
When fresh water washes in and dissolves the salts, cavities are created, causing sinkholes.
Detecting potential sinkholes is crucial because they not only damage the environment, but pose a direct threat to the tourist industry and agriculture.
These underground pits can now be better detected by a new monitoring system.
SOUNDBITE (English) Lev Eppelbaum, Dept. of Geophysics & Planetary Sciences, Tel Aviv University: "We developed a methodology of combining geophysical prediction of sinkholes appearing at the Dead Sea costal plane. What we have (as) a problem now is we need to create at least (a) few geophysical teams with the aim of constant geophysical monitoring of the dangerous area."
The Geophysical Institute of Israel, along with the Geological Survey of Israel, have been trying to locate sinkholes when they are being created and to follow them. The monitoring can help reveal dangerous sinkhole zones in their early stages.
When a sinkhole is deemed dangerous, reportedly, crews can fill it with cement or initiate its collapse before it would happen naturally.
In the 80 years that records have been kept, the water level in the Dead Sea has dropped by over 65 feet. The sea has shrunk by more than a third.
And in the absence of any expensive water replenishment plan, the sea is expected to shrink to about two-thirds of its current size over roughly the next century.