During the SN1987A explosion on February 23, 1987, four underground neutrino detectors and two gravitational antennas in Rome and Maryland detected signals associated with the gravitational collapse of the star’s core. Because it is impossible to detect direct gravitational radiation from the collapse of SN1987A with antennas, it is still unclear what events were recorded by gravitational antennas. In this work, an amplitude analysis of the signals from gravitational antennas in Rome and Maryland in the vicinity of the signals from neutrino detectors during Supernova SN1987A was carried out. It is shown that the amplitude distributions in all antenna signals are consistent with the distribution of fluctuating energy losses of atmospheric muons crossing the antennas. A conclusion has been made about the muon origin of signals Weber type antennas, aluminized cylinders with a mass of 2–3 t.