The Nuweiba earthquake (Mw = 7.1) of November 1995 had significant effects on groundwater heads, spring discharge, and chemistry in the Dead Sea Rift Valley. Groundwater heads increased by 6 cm near the Dead Sea (local shallow alluvial aquifer) and by 50 cm near the sea of Galilee (regional deep confined aquifer), some 330 and 460 km north of the epicenter, respectively. In the arid central Arava valley, some 210 km north of the epicenter, the discharge of small springs increased significantly. The increase in spring discharge, as recorded in Moa spring, was accompanied by a marked change in its chemistry. However, while the change in discharge followed the earthquake, the chemistry change was found some 16 days before the earthquake. The effect of the earthquake in Moa was enhanced and prolonged because of a breach in the confinement system of the shallow artesian aquifer and the formation of new flow paths along faults, cracks, and dikes. Due to the extreme aridity of the region, the sequence above the aquifer is loaded with soluble salts. Dissolution of these salts by the ascending groundwater accounts for the observed increase in salinity and changes in the spring chemistry with time. Initially, the ascending water flushed the newly formed flow paths, gradually leaching the available soluble salts. Later, as discharge shrank, upward flow was maintained within the already flushed system, and the water chemistry returned to the original aquifer composition.
|Pages (from-to)||ETG 4-1 - 4-10|
|Journal||Journal of Geophysical Research: Solid Earth|
|State||Published - 10 Dec 2002|
- Water discharge
- Water level