THE DETECTION OF MONUMENTAL TOMBS BURIED IN TUMULI BY SEISMIC REFRACTION

A tumulus is a construction erected to cover a tomb. Some tumuli are i mpressively massive and may conceal architectural masterpieces. Seismi c refraction is employed to locate the tomb and to allow selective exc avation without destroying the tumulus. The detectors are spread along a circular profile on the periphery of the tumulus, and acoustic wave s are generated on its top. Time delays observed in the arrivals of th e headwaves reveal the position of the monument. The delays are not ca used by the monument itself, but are an effect caused by the presence of a ramp that was dug in the undisturbed soil to help in the construc tion of the tomb. Three case histories in Northern Greece establish th e efficiency of the technique. In the first example, an experiment was conducted at a previously excavated tumulus, and time delays attribut ed to the revealed ramp are observed. The second case study led to the discovery of an impressive monument; 3-D modeling by-finite differenc e verifies the interpretation. A third study is also reported; where, for the most promising portion of the data, 3-D modeling has been perf ormed.