A tornillo event is a low-frequency seismic event associated with volcanoes. The term, which means "screw" in Spanish, was coined in the mid-1990s at the Observatorio Vulcanológico y Sismológico de Pasto (OVSP) in Pasto, Colombia to describe seismic events seen at the Galeras volcano.

A tornillo has the following characteristics that distinguish it from other seismic events:

Like volcanic tremor, tornillos are thought to be caused by magma moving at depth.

References

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  1. Tornillo-type seismic signals at Galeras volcano, Colombia, 1992−1993
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