Abstract

The word “tephra” is an all-encompassing term for the explosively erupted, pyroclastic (fragmental) products of a volcanic eruption. Since the early pioneering work of Thorarinsson and others, the value of tephras in providing time-parallel marker horizons or isochrons is now well understood. Tephras are routinely detected and identified in both visible and non-visible (cryptotephra) forms, and are used in a diverse range of disciplinary fields including stratigraphy, sedimentology, geomorphology, archeology, and paleoenvironmental reconstruction over a wide range of time scales. Tephrochronology is also an essential tool for establishing the frequency/periodicity of volcanic activity and for assessing volcanic hazards.