Event Name : Dutton Debris Avalanche
|Start: 5080 (± 100 Years) || Years BP C-14 (raw) || |
|Stop: 6800 (± 100 Years) || Years BP C-14 (raw) || |
|Debris-avalanche, volcanic avalanche, or landslide: ||
|Eruption Type:||Not an eruption.|
From Miller and others (1999): "As much as 0.3-0.5 km cubed of material slid off the western part of the upper edifice; the deposit has been dated at between 5080+/-100 and 6800+/-100 14 C yBP (Miller and others, 1999) and is probably closer to the latter age based on stratigraphic position."
"Debris avalanche deposits occur on the northwest and south flanks of the volcano Fig. 1 [of original text] where they underlie a total area of about 14 km square and have a combined volume of about 0.4 km cubed. The deposits in both areas are characterized by blocks as large as 10 m, enclosed in a poorly sorted matrix or lying on the surface. Megaclasts consist chiefly of cone-building andesitic lava Qcbf with some subordinate dacite. The dacite clasts are not prismatically fractured nor do they display other evidence of being hot, juvenile magmatic material at the time of the avalanche; their presence, however, is evidence that one or more domes had been emplaced before the edifice collapse that resulted in these deposits."
"The avalanche deposits are non-glaciated and are mid-Holocene in age. The similarity in clast size and composition and their proximity suggests the two deposits are of similar age, i.e., between 5080 and 6800 14C yBP (Miller and others, 1998, 1999)."