Four Plinian eruptions from Ksudach volcano ha' been reconstructed and dated by the 14C method. Three collapse calderas formed as a resu of these eruptions: KSi and caldera V 1700-1800 yrs ago; KS2 + KS3 and caldera IV 6000- 6100 yrs ago; KS4 and caldera III 8700-8800 yrs ago. KSi was the most voluminous eruptio with 18-19 km of pyroclastics and column height reaching 23 km. The volume of produci of KS2 + KS3 was 10-11 km3 and that of KS4, at least 1.5-1.7 km3. Sizes of calderas wer as follows: V - 4 X 6.5 km, IV - 5x5 km, III - presumably 2-3 km across. The juveni pyroclastics were supplied during eruptions rather rhythmically. Each rhythm began wil tephra ejection and completed with the formation of pyroclastic flows. The composition < products varied from andesited to rhyodacites: KS2 and KS4 - andesites dominated, KS3 - dacites and rhyodacites, and KSi - rhyodacites. It is possible that "the mechanism triggering onsets of all caldera-forming eruptions was the intrusion of very hot fresh magma of basi composition and its mixing with less hotter acid magma in the magma chamber existe previously. The eruptions, in accordance with their scales, may have had an impact on clima and ozone layer of the Earth. It is likely that the large acidity peaks in Greenland ice cor* result from these eruptions.

The actual collective monograph presents the results of both theoretical and experimental studies of the multi-disciplinary problem on volcanic hazard assessment and development of techniques for prediction of catastophic eruptions. The volcanism of Kamchatka and other regions of Russia has been analyzed. On the basis of geological, volcanological and tephrachronological studies including radiocarbon dating, there have been defined certain groups of volcanoes on different stages of evolution. At the same time the problem of determination of the internal structure of volcanic dome using modem theoretical methods and technologies is well investigated. The new techniques of estimation of volcanic hazard were developed. Whenever ti is required, theoretical approaches are confirmed by results of in-field observations.

The book will satisfy the needs of Earth sciences specialists from a variety of backgrounds, volcanology, geo-mechanics, ecology, industrial constuction applications and hazard assessment.

Tephrochronological and radiocarbon investigations of soil-pyroclastic depositsalong the line Shiveluch Volcano - Chernyi Yar - Bering I. have detected and identified the ashes oflargest (for the past 6500 years) eruptions on Shiveluch Volcano in the southeastern sector of the ashabundance area, as well as the ashes of Bezymyannyi, Ksudach, Klyuchevskoi, Avacha and Khangarvolcanoes. A detailed radiocarbon dating of peat deposits in Chernyi Yar has not only improved the agedeterminations of the eruptions themselves but also helped in the determination of ash fall rate for thelower Kamchatka R. valley, namely, once in 191 years. Apart from the 1964 tephra, we suggest for useas regional geochronological markers the ash horizons of Shiveluch Volcano having the followingrounded radiocarbon dates: 265 (SH1), 965 (SH2), 1450, 2800, 3600 (SP), 4105 (SHDV), 4800, as well asthe ashes from Ksudach 1806 (KS1) and Avacha 5489 (AV2) volcanoes.