The chronology, dynamics, and parameters of seven large eruptions of Avacha Volcano were reconstructed for its IAv andesitic period 7250-370014C years B.P., which began after a >2000-year period of relative quiescence. Their juvenile (andesitic pyroclastics) and resurgent products are described, and the geological and geomorphological consequences are evaluated. The largest eruption occurred 715014C years B.P. (8-10 km3 of erupted material). The subsequent events occurred 5700 (≥0.34 km3), 5600 (≥0.4 km3), 5500 (>1.34 km3), 5000 (≥0.5 km3), 4500 (>1.1 km3), and 4000 (≥0.6 km3) 14C years B.P. The erupted rocks were dominated by tephra; pyroclastic flows occurred only during the events of 5500 and 5000 years ago. It is believed that most of the eruptions produced acid peaks of varying intensity in the Greenland ice sheet.

per presents radiocarbon data obtained at the Institute of Volcanology and Institute of Geology, USSR Academy of Sciences , from 77 samples of carbon, wood, and burried soil taken during tephrochronological investigations of soil-pyroclastic covers at the foot of Karymskii and Malyi Semyachek Volcanoes. The authors show the tables of radiocarbon data indicating the main events of the volcanoes as well as the sections showing the position of the dated samples. The accuracy of the radiocarbon dating is discussed. The diagram of soil-pyroclastic cover at the foot of Malyi Semyachek is considered to be as standard for East Kamchatka volcanic zone. Palyno-logical complexes are distinguished; they are dated and adjusted to perioda according to Blitt-Sernander scale.