A series of mysterious underground booms have been rattling a small eastern Wisconsin city for at least two nights, baffling residents and local officials who were left stumped Tuesday after ruling out numerous theories, from earthquakes to water pressure problems.
The noises - described as rumbles of thunder, sonic booms or fireworks - were being reported in northeast Clintonville, about 140 miles northwest of Milwaukee, on Sunday night but quieted down at daybreak. The sounds started back up Monday night across a wider area and continued until about 5 a.m. Tuesday, said City Administrator Lisa Kuss.
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