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Challenges Facing Discovery of Largest Lake in World History Geotechnical Investigation

Earthquakes as one of important Natural hazards, has caused the destruction of Tehran (Ray civilization) in history. However, extensive studies conducted in the recent decade reject all previous findings about the cause of these incidents. Paleoseismological studies show that the escarpment of North Rey, South Rey and Kahrizak faults have no evidence of faulting but they are paleoshorelines.

Recent studies show the relation between civilizations location and the ancient Lake shorelines. This has resulted in discover of the largest ancient lake in world history. Today, the lake is known as the Paleo Mega Lake of Rey (PAMELA).

Subsidence, as the other destructive natural hazard, has also created problems for Tehran. PAMELA sediments are mostly made of clay and silt and have a high potential for subsidence if lost water. In this study, we investigate the relationship between the PAMELA sediment thickness and the subsidence rate. The method of this research is Vertical Electric Sounding to identify the depth of sediments. Then the correspondence between these findings and the subsidence data in the area is examined.

Geophysical profiles in the western part of Tehran plain show that PAMELA sediments can be traced to a depth of more than 120m to 8m in the east. This is due to the low depth of bedrock in the eastern part of Tehran plain because there is no noticeable difference in topography on the surface. On the other hand, from east to west in the Tehran plain, the rate of subsidence, according to available resources, increases from 10 cm/y to 25 cm/y. The main cause of the subsidence in Tehran plain is PAMELA sediments and changes in their thickness. Due to the high sensitivity of these clay sediments to water loss and subsidence, it seems necessary to investigate the distribution of these sediments in the whole country of Iran.

Session: The Effects of Sedimentary Basins on Earthquake Ground Motions [Poster]

Type: Poster

Room: Evergreen Ballroom

Date: 4/20/2022

Presentation Time: 08:00 AM Pacific

Presenting Author: Mehmet Salih Bayraktutan

Student Presenter: Yes

Additional Authors