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Abstract. Near-surface geophysical imaging of alluvial fan settings is a challenging task but crucial for understating geological processes in such settings. The alluvial fan of Ghor Al-Haditha at the southeast shore of the Dead Sea is strongly affected by localized subsidence and destructive sinkhole collapses, with a significantly increasing sinkhole formation rate since ca. 1983. A similar increase is observed also on the western shore of the Dead Sea, in correlation with an ongoing decline in the Dead Sea level. Since different structural models of the upper 50 m of the alluvial fan and varying hypothetical sinkhole processes have been suggested for the Ghor Al-Haditha area in the past, this study aimed to clarify the subsurface characteristics responsible for sinkhole development.For this purpose, high-frequency shear wave reflection vibratory seismic surveys were carried out in the Ghor Al-Haditha area along several crossing and parallel profiles with a total length of 1.8 and 2.1 km in 2013 and 2014, respectively. The sedimentary architecture of the alluvial fan at Ghor Al-Haditha is resolved down to a depth of nearly 200 m at a high resolution and is calibrated with the stratigraphic profiles of two boreholes located inside the survey area.The most surprising result of the survey is the absence of evidence of a thick (> 2–10 m) compacted salt layer formerly suggested to lie at ca. 35–40 m depth. Instead, seismic reflection amplitudes and velocities image with good continuity a complex interlocking of alluvial fan deposits and lacustrine sediments of the Dead Sea between 0 and 200 m depth. Furthermore, the underground section of areas affected by sinkholes is characterized by highly scattering wave fields and reduced seismic interval velocities. We propose that the Dead Sea mud layers, which comprise distributed inclusions or lenses of evaporitic chloride, sulfate, and carbonate minerals as well as clay silicates, become increasingly exposed to unsaturated water as the sea level declines and are consequently destabilized and mobilized by both dissolution and physical erosion in the subsurface. This new interpretation of the underlying cause of sinkhole development is supported by surface observations in nearby channel systems. Overall, this study shows that shear wave seismic reflection technique is a promising method for enhanced near-surface imaging in such challenging alluvial fan settings.

Background & Aim: Bariatric surgery is a valid treatment option for persons with non-alcoholic fatty liver disease. This study prospectively examined the impact of laparoscopic sleeve gastrectomy (LSG) on liver histopathology, and blood levels of adiponectin, leptin, resistin, and pre-B cell enhancing factor/Nampt/visfatin. Patients & Methods: In 81 patients with non-alcoholic fatty liver disease who underwent LSG, paired liver biopsies and blood specimens were obtained before and 18 months after LSG. Differences between preoperative and 18 months postoperative data were tested by paired Student's t-test or Wilcoxon rank test as appropriate. Results: At follow up, there was a significant improvement in biochemical markers for glucose homeostasis, including fasting glucose, HbA1c, insulin levels, and homeostatic model assessment index. Postoperative liver function tests, namely serum alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase level, showed a significant improvement compared to before weight loss. The number of patients who had definite, borderline, or no non-alcoholic steatohepatitis was 43 (53%), 27 (33%), and 11 (14%), respectively, at baseline, and 9 (11%), 32 (40%), and 40 (49%) at 18-month postsurgery follow up. A significant reduction in steatosis, liver fibrosis, lobular inflammation, and hepatocyte ballooning was observed in the postoperative biopsies (P < 0.001 each). In addition, at the follow-up assessment, there was a significant increase in serum adiponectin levels and significant decline in serum levels of leptin, resisitin, and pre-B cell enhancing factor/Nampt/visfatin. Conclusion: Weight loss after sleeve gastrectomy was associated with a significant improvement in several metabolic parameters, liver enzyme levels, liver histopathology, and changes in serum adipokine levels towards antidiabetic and anti-inflammatory profiles.

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