Application of Multi-Channel Analysis Surface Waves and Electrical Resistivity Tomography Methods to Identify Weak Zones at University of Mosul, Northern Iraq

Cracks have been developed in a large lecture hall on the University of Mosul Campus. These cracks exist along two sides building. Multi Analysis Surface Wave and Electrical Resistivity Tomography surveys were conducted at surrounding building to investigate nature distribution shallow subsurface soil/rock. The MASW’s data show three layers: first layer is characterized by low shear wave velocity ranges between 210 420 m/s which attributed infill materials, next river terrace (fairly competent rock) has Vs ranging from 430m/s 840 m/s. It recognized gradual increase mechanical characteristics as depth increases. In-depth about 2.5m 6.0 m drops top contact this layer. causes may be due weathering medium because sinkhole. profile shows four electrical zones, zone 50-70 Ω.m. with variable thickness 0.5-1.5 indicates materials. second very resistivity value, 0.5m - 3.5 m, might interpreted increased clay, silt water content (high water-saturated zone). third high-resistivity value (>100 Ω.m) that could related dry conglomerate rock gravels belong terraces. fourth low-resistivity (<20 associated marl bed. We definitively correlated anomalies sinkhole activity identified using combined geophysical methods. Waves shown complete each other evaluation. variations (low velocity) (conductive zone) within detected proposed indicative dissolution subsidence responsible for structural damage implied change resistivity. roughness surface strongly influences values. This suggestive or erosion.