Collapse of the Dead Sea coaMore than 1000 sinkholes

Y. Yechieli, M. Abelson, A. BeinV. Shtivelman, G. Baer, D. Wachs

O. Crouvi, R. Calvo

Florida

Russia

Thailand

After the Tsunami

Dead Sea sinkholes – Regional-scale observations

Sinkholes in mud flatsShalem-2 site (Mineral Beach)

Neve Zohar

Hever south

Sinkholes in alluvial fans

Sinkhole collapse beneath a borehole

Hever-south site

~1.5 m

… a week later

Ein Gedi Camp site

Ein Gedi date plantation

Sinkhole sites along

The Dead Sea coast

sinkhole site

In the last 4 years: Growth rate of 150-200 sinkholesper year in the northern basinSo far, ~1000 sinkholes were identified

Growth rate of sinkholes along the Dead Sea coast

Acceleration

areaIncrease in total sinkhole

numberIncrease in sinkhole

Formation mechanism

Dissolution of soluble rock

Winter Park, Florida (1981)

Hever-2

(south of Heverfan)

Salt from Neve-Zohar sinkhole site

Retreat of Dead Sea coastline&

formation sinkholes

En Gedi

Na/Cl=0.55

Na/Cl=0.33

Cl=220 g/l(Dead Sea

water)

Cl=15 g/l(Fresh water)

Mineral-2 borhole

Photograph ofcavity wall

Penetration of under saturated ground

water through aquiclude layers

Sinkholes on

faults

Hever-2

(south of Heverfan)

Aquicludic layers coating

the salt layer

Shtivelman (2002)

Intactblock

Risk zonation

Ein-Gedi

Based on data from boreholes, the westernmost sinkhole sites trace the

western boundary of salt layer

En GediShalem-2

DargaNeve Zohar

The western boundary of salt layer distribution

Development of sinkhole sites vs. altitude

Date of sinkhole site first appearance01/1978 01/1980 01/1982 01/1984 01/1986 01/1988 01/1990 01/1992 01/1994 01/1996 01/1998 01/2000 01/2002

Ele

vatio

n of

sin

khol

e si

te c

entro

id (m

)

-415

-410

-405

-400

-395

-390

-385

-380

Sinkhole site average heightDead sea level

Hever fan 3

ArugotNewe Zohar

Hever southYeelim

Lintch

Mor

Lisan channel

Hever northMishmar

Asael

Zeelim 1 Shalem 2

Zeelim 4

Zeelim 3

YeshaSamar

Kane north

Zeruya

Zeelim 2

Kane 3, Shalem 3

Avnat, Shalem 4Shalem 1, Zukim

Mazor

Dragot south

Kane 2

Hever fan 2

Zeelim fan 1-2

Kane1,Avenat south

Ein Bokek

Alluvial fans

-400 m

Dead Sea level

-400 m

Western margin crosses alluvial fan

En Gedi area

Darga-Hatsatsonalluvial fan

Hever alluvial fan

Hever fan

מניפת חבר�אזור סיכון

Future perspective

●More than 1000 Sinkholes in a narrow strip, 60 km long & <1km width, along the Dead Sea coast, clustered in ~40 sinkhole sites

Summary

● Sinkholes form due to dissolution of salt layer triggered by the shrinkage of the Dead Sea, attested by findings of cavities in salt layer & undersaturated groundwater below it

● Sinkholes develop above concealed faults

● Early sinkhole sites trace the westernmost boundary of salt layer, in level of -400 m, assisting in definition of risk zonation.

● Sinkhole development may cease when groundwater level will decline below the salt layer, assuming no deeper salt layers

Thank you