Universita' di Bologna, v.le Risorgimento n.2, Bologna, 40136 Italy ; St. Anthony Falls Lab, and Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Dr. SE, Minneapolis, MN 55455 United States
St. Anthony Falls Lab, and Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Dr. SE, Minneapolis, MN 55455 United States
St. Anthony Falls Lab, and Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Dr. SE, Minneapolis, MN 55455 United States