Herbert Island description and information

From Wood and Kienle (1990): "Herbert is a classic stratovolcano with a 2.1-km-wide caldera, which the topographic map indicates is breached to the northwest. Radar images do not show the breach. No geologic studies have been published on this volcano. A grab sample from the tip of the island's southwest point is an andesite (59% SiO2, with 0.82% K2O)."