Volcanoes and their hazard to aviation

In March 2013, the Kamchatkan Volcanic Eruption Response Team (KVERT) celebrated the 20th anniversary of its activity. This team, which was created by the joint efforts of Russian and American scientists, analyzes on a daily basis the data supplied by the complex (seismic, video, visual, and satellite) monitoring system of volcanoes of Kamchatka and the Northern Kuril Islands to notify airline companies and all interested organizations about potential hazards

Degassing explosions at Karymsky Volcano, Kamchatka

During the summer of 1997, Karymsky Volcano produced summit explosions about six times each hour. Typical explosive episodes lasted between 30 seconds and three minutes, produced gas and ash columns several hundred meters high, and ejected some incandescent material. To better understand the physical source mechanisms responsible, we recorded hundreds of explosions with a three component broad-band seismometer and microphone located 1650 meters from the active vent. Nearly every explosion is recorded as an emergent yet identical seismic wavelet which is followed 4.15 s later by an impulsive acoustic arrival. We interpret the signals as a near-surface gas volume burst which fractures the vent 'plug,' lowers the lithostatic pressure within the magma column, and often induces further degassing. When degassing continues, it is generally manifested as either a series of regular one second 'chugging' explosions, steady higher frequency 'jetting', or a hybrid combination. We believe that the seismic signature for 'chugs,' short duration harmonic tremor with integer overtones, is the result of repeated gas volume bursts at the vent. In contrast, seismograms for jetting are non-harmonic and contain higher frequencies. We believe that the competing degassing behaviors are influenced by the gas flux as well as the plug/conduit characteristics. We propose that a plug exists due to a viscosity gradient caused by volatile depletion in the upper conduit.During the summer of 1997, Karymsky Volcano produced summit explosions about six times each hour. Typical explosive episodes lasted between 30 seconds and three minutes, produced gas and ash columns several hundred meters high, and ejected some incandescent material. To better understand the physical source mechanisms responsible, we recorded hundreds of explosions with a three component broad-band seismometer and microphone located 1650 meters from the active vent. Nearly every explosion is recorded as an emergent yet identical seismic wavelet which is followed 4.15 s later by an impulsive acoustic arrival. We interpret the signals as a near-surface gas volume burst which fractures the vent 'plug', lowers the lithostatic pressure within the magma column, and often induces further degassing. When degassing continues, it is generally manifested as either a series of regular one second 'chugging' explosions, steady higher frequency 'jetting', or a hybrid combination. We believe that the seismic signature for 'chugs,' short duration harmonic tremor with integer overtones, is the result of repeated gas volume bursts at the vent. In contrast, seismograms for jetting are non-harmonic and contain higher frequencies. We believe that the competing degassing behaviors are influenced by the gas flux as well as the plug/conduit characteristics. We propose that a plug exists due to a viscosity gradient caused by volatile depletion in the upper conduit

Analysis of argon concentration anomalies in underground water in Kamchatka (Russia)

In this paper we present the results of characterising time series of the argon content of groundwater recorded in the Kamchatka area of Russia. The problems of correlating anomalies in the argon data with seismic activity are explored. A new statistical technique for relating anomalies to geophysical observations based on Markov Chain Monte Carlo modelling methods is outlined

Groundwater helium content related to the Spitak (Armenia) and Karymsky (Russia) earthquakes

The Spitak and Karymsky earthquakes occurred with M46.9 in Armenia and in Kamchatka (Russia), respectively. As regards the Spitak earthquake, we analysed the groundwater helium content data collected by three Georgian and one Armenian measurement sites; as regards the Karymsky earthquake, we analysed the groundwater helium content data collected by two measurement sites in Kamchatka. The first analysis has pointed out that precursory anomalies appeared in the northern area with respect to the Spitak epicentre; on the contrary, only co-post seismic anomalies were revealed in the southern area. As regards the Karymsky earthquake, no pre-co-post seismic variation in the groundwater helium content was revealed at both the measurement sites. The analysis of other hydrogeochemical parameters, collected in these sites, revealed that one site does not show any anomaly; on the contrary, at the other measurement site clear preseimic anomalies appeared in some hydrogeochemical parameters. A possible explanation of the quoted results is presented

Groundwater Argon content on the occasion of strong earthquakes in a seismogenetic area of Kamchatka (Russia)

Since 1988 the argon content in underground water has been measured at the Morosnaya well, in the Kamchatka peninsula, with a sampling frequency of three days. In the same well other gases and ions dissolved in water are measured, together with flow rate, pH and temperature. The most active seismogenetic area in Kamchatka is that located offshore, along the south-eastern coast of the peninsula. The strongest earthquakes in this area occurred on March 2, 1992 (M47.1), November 13, 1993 (M47.0) and June 21, 1996 (M47.1), within a distance of 200 km from the well. The focal depth of the earthquakes of 1992 and 1993 was 20 and 40 km, respectively. The earthquake which occurred in 1996 was very shallow; a focal depth of few kilometres was estimated. No anomalies in the argon or other dissolved gas concentration were observed on the occasion of 1992 and 1993 earthquakes; on the other hand, a very clear preseismic anomaly appeared in the concentration of argon and nitrogen on the occasion of the 1996 earthquake. The behaviour of the ion content was opposite; no anomaly on the occasion of the last earthquake and clear preseismic anomalies on the occasion of the two former earthquakes appeared. A possible explanation of the quoted behaviour of dissolved gases and ions in groundwater according to the different focal depth of the subsequent earthquakes is presented