Great Sitkin reported activity

Event Name : Great Sitkin Forty Year Ash

Start: 200

Years BP Tephrochronology

Tephrafall:

Description: From Kiriyanov and Miller (1997): "AD-1 has a thickness of 6-10 cm and consists of a pinkish-gray clay- or silt-size material containing lenses of fine-grained volcanic sand. The main components are volcanic glass (69%) and plagioclase (21%). The characteristic features are a significant amount of pyroxenes (6%) and absence of green or brown hornblend (Fig. 5 [in original text]). More than 50 wt. % of the sample are particles smaller than 0.071 mm in size. The glass is colorless, juvenile, and contains microlites of plagioclase. The approximate carbon-14 age of the ash is less than 200 years (P. Black determined its carbon-14 age of 40 years, Table 1 [in original text])."