Developing chronologies for sediments in the Arctic Ocean and its continental margins is an important but challenging task. Tephrochronology is a promising tool for independent age control for Arctic marine sediments and here we present the results of a cryptotephra study of a Holocene sedimentary record from the Chukchi Sea. Volcanic glass shards were identified and quantified in sediment core HLY0501-01 and geochemically characterized with single-shard electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). This enabled us to reveal a continuous presence of glass shards with identifiable chemical compositions throughout the core. The major input of glasses into the sediments is geochemically fingerprinted to the ∼3.6 ka Aniakchak caldera II eruption (Alaska), which provides an important chronostratigraphic constraint for Holocene marine deposits in the Chukchi-Alaskan region and, potentially, farther away in the western Arctic Ocean. New findings of the Aniakchak II tephra permit a reevaluation of the eruption size and highlight the importance of this tephra as a hemispheric late Holocene marker. Other identified glasses likely originate from the late Pleistocene Dawson and Old Crow tephras while some cannot be correlated to certain eruptions. These are present in most of the analyzed samples, and form a continuous low-concentration background throughout the investigated record. A large proportion of these glasses are likely to have been reworked and brought to the depositional site by currents or other transportation agents, such as sea ice. Overall, our results demonstrate the potential for tephrochronology for improving and developing chronologies for Arctic Ocean marine records, however, at some sites reworking and redistribution of tephra may have a strong impact on the record of primary tephra deposition.

Geochemically fingerprinted widespread tephra layers serve as excellent marker horizons which can directly link and synchronize disparate sedimentary archives and be used for dating various deposits related to climate shifts, faulting events, tsunami, and human occupation. In addition, tephras represent records of explosive volcanic activity and permit assessment of regional ashfall hazard. In this paper we report a detailed Holocene tephrochronological model developed for the Kamchatsky Peninsula region of eastern Kamchatka (NW Pacific) based on ∼2800 new electron microprobe analyses of single glass shards from tephra samples collected in the area as well as on previously published data. Tephra ages are modeled based on a compilation of 223 14C dates, including published dates for Shiveluch proximal tephra sequence and regional marker tephras; new AMS 14C dates; and modeled calibrated ages from the Krutoberegovo key site. The main source volcanoes for tephra in the region are Shiveluch and Kliuchevskoi located 60–100 km to the west. In addition, local tephra sequences contain two tephras from the Plosky volcanic massif and three regional marker tephras from Ksudach and Avachinsky volcanoes located in the Eastern volcanic front of Kamchatka. This tephrochronological framework contributes to the combined history of environmental change, tectonic events, and volcanic impact in the study area and farther afield. This study is another step in the construction of the Kamchatka-wide Holocene tephrochronological framework under the same methodological umbrella. Our dataset provides a research reference for tephra and cryptotephra studies in the northwest Pacific, the Bering Sea, and North America.

Ash clouds resulting from explosive volcanic eruptions pose a real threat to human (for aircraft flights, airports operations, etc.); therefore, the detection, monitoring, and forecast of their movement is an urgent and important issue. The features and examples of application of the new tool developed on the basis of "Monitoring of active volcanoes of Kamchatka and the Kurile Islands" information system (VolSatView) are described. It allows the integrated monitoring and forecasting of ash cloud transport using the data of remote sensing and mathematical modeling as well as the assessment of the parameters of explosive events.

Satellite based remote sensing of active volcanoes has been performed in various forms since 1965. Compared to “on the ground” observations it lets data to be gathered globally at regular pace for long periods of time without the need for local maintenance. Currently existing publicly available volcanoes thermal activity monitoring systems rely on the detection algorithms narrowly specified for volcanoes temperature ranges and operate using the data from previous generation of sensors, which is supported with non-reserved constellation of two satellites. The presented work proposes pipeline (the sequence of actions) based on the clustering of the data received from the Nightfire thermal anomalies detection algorithm, which is not focused on the specific type of infrared sources. Pipeline has been tested on Kamchatka’s region 2016 year dataset and proved to produce sound results corresponding to manual observations.

Действующие вулканы Камчатки ― одни из самых активных в мире. Ежегодно здесь происходят извержения 3−7 вулканов, во время которых эксплозии поднимают пепел до 10−15 км над уровнем моря и пепловые облака распространяются на тысячи километров от вулканов. Активная вулканическая деятельность может стать причиной пеплопадов в городах и поселках, уничтожения лесов и коммуникаций. Пепловые облака и шлейфы представляют серьезную опасность для полетов современной реактивной авиации. Для снижения вулканоопасности для авиаперевозок и населения с 1993 г. Камчатская группа реагирования на вулканические извержения (KVERT) выполняет ежедневный мониторинг вулканов. С 2014 г. спутниковый мониторинг вулканов проводится учеными KVERT с помощью информационной системы VolSatView, в которую с 2016 г. начали поступать данные с геостационарного спутника Himawari-8. В системе созданы специальные инструменты, позволяющие работать с оперативно поступающими данными и анализировать ряды долговременных наблюдений. Применение данных Himawari-8, а также инструментов, реализованных в VolSatView для работы с ними, позволяет: значительно повысить оперативность обнаружения эксплозивных событий, происходящих в регионе; определять начало эруптивных событий с точностью до 10 и менее минут; отслеживать и прогнозировать все изменения динамики активности вулканов, в том числе близкое начало сильных эксплозивных событий. Статья посвящена описанию особенностей технологии интеграции данных Himawari-8 в VolSatView и основным возможностям работы с ними, реализованным в настоящее время в системе.