DITAG

Bathymetry and bottom sediment types of inland water basins provide meaningful information to estimate water reserves and possible connections between surface and groundwater. Waterborne geophysical surveys can be used to obtain several independent physical parameters to study the sediments. We explored the possibilities of retrieving information on both shallow and deep geological structures beneath a morainic lake by means of waterborne nonseismic methods. In this respect, we discuss simultaneous magnetic, electrical, and ground-penetrating radar (GPR) waterborne surveys on the Candia morainic lake in northerly Turin (Italy). We used waterborne GPR to obtain information on the bottom sediment and the bathymetry needed to constrain the magnetic and electrical inversions. We obtained a map of the total magnetic field (TMF) over the lake from which we computed a 2D constrained compact magnetic inversion for selected profiles, along with a laterally constrained inversion for one elect...

This volume is dedicated to the memory of Roger Adams Young (1943-2009). Roger was an outstanding professor and colleague who committed his career to teaching, mentoring, research, and service. His selflessness, integrity, and kindness made him one of the most valued members of our near-surface community.

A comparative study of the seismic behavior of “cla ssical” full containment LNG and membrane technolog y tanks is presented in this paper. The aim of the study is to evaluate the seismic response of the two technolog ies in areas subjected to severe seismic conditions. A 9%Ni full containment tank and a membrane tank fi tted with GST technology were analyzed. They are of similar net volume capacity of approx 180,000 m 3 and considered as resting on the same soil stratig raphy. Due to the poor site soil conditions, stone columns and vertical drains are r equi ed to increase foundation capacity and reduce settlements. The seismic analysis is developed in a two-step app roach with increasing accuracy, i.e. 1) following t he simplified procedure reported in Eurocode 8, with references t o other standards, in which the spring-mass analogy is considered, and 2) a detailed finite element model of the tanks i order to obtain the internal wall actions and t he distribution of the soil press...

The paper reports on the use of surface-wave testing for the construction of a three-dimensional (3D) shear-wave velocity model of an alluvial basin. The town of Tarcento (Italy) is located in a region with a high level of seismic hazard and was strongly affected by the two Friuli earthquakes in 1976. The seismic surveys were performed with surface-wave multistation methods using a combination of active-source and passive-source experimental setup. Experimental data were collected at 16 sites, and inversion of the data is based on an innovative procedure for spatially constrained inversion with a single objective function in which a priori information is included. The method provides an improvement in the robustness of the solution, mitigating solution nonuniqueness. Available borehole logs at different locations are integrated into the data set in terms of a priori bedrock information. Three independent cross-hole tests are used for a posteriori comparison of the inverted one-dimensional (1D) profiles. Three-dimensional interpolation of the obtained profiles leads to a shear-wave velocity model that is internally consistent and complies with a priori information, cross-hole results, and suitable boundary profiles. The model is intended for numerical simulations of the seismic response of the basin.