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1.
Kamchatka and the Kuril Islands are home to 36 active volcanoes with yearly explosive eruptions that eject ash to heights of 8 to 15 km above sea level, posing hazards to jet planes. In order to reduce the risk of planes colliding with ash clouds in the north Pacific, the KVERT team affiliated with the Institute of Volcanology and Seismology of the Far East Branch of the Russian Academy of Sciences (IV&S FEB RAS) has conducted daily satellite-based monitoring of Kamchatka volcanoes since 2002. Specialists at the IV&S FEB RAS, Space Research Institute of the Russian Academy of Sciences (SRI RAS), the Computing Center of the Far East Branch of the Russian Academy of Sciences (CC FEB RAS), and the Far East Planeta Center of Space Hydrometeorology Research (FEPC SHR) have developed, introduced into practice, and were continuing to refine the VolSatView information system for Monitoring of Volcanic Activity in Kamchatka and on the Kuril Islands during the 2011–2015 period. This system enables integrated processing of various satellite data, as well as of weather and land-based information for continuous monitoring and investigation of volcanic activity in the Kuril–Kamchatka region. No other information system worldwide offers the abilities that the Vol-SatView has for studies of volcanoes. This paper shows the main abilities of the application of VolSatView for routine monitoring and retrospective analysis of volcanic activity in Kamchatka and on the Kuril Islands.  相似文献   

2.
The formation of the hydrothermal system in the Valley of Geysers is shown to be governed by a structure of radial and circular faults of above-intrusion zone of a partially melted magmatic body with an epicenter near the Upper-Geyser Field, while the hydrothermal system is shown to receive its water from elevations of +500 to +900 m abs (according to isotopic data). The catastrophic landslide of June 3, 2007, was just a stage in the general scenario of the gradual hydrothermal transformation of the inclined Geyser unit (Q 3 4 grn), building up the roof of the hydrothermal reservoir, with a gradual decline of slide resistance. The slide was triggered by the increased pressure in the hydrothermal and magmatic systems and the saturation of the Geyser unit by moisture during spring flood. According to the data of continuous regime thermohydrodynamic observations carried out in the Valley of Geysers with the use of HOBO-loggers of temperature and pressure since July 2007 to April 2010, the mean time between eruptions of Velikan geyser was 348 minutes. The intensification of precipitation input directly into the geyser pool causes a short-time increase in the time between eruptions (up to the maximum of 32 h). According to observations at the “Plotina” gage, the total estimated mean annual discharge of thermal springs (by chlorine ion) in the Valley of Geysers is 263 kg/s; the discharge of thermal springs is governed by the level of Poldprudnoe Lake and its seasonal variations exceed 40%.  相似文献   

3.
This is a review of the geodetic monitoring of the horizontal component of recent crustal movements (RCMs) in Kamchatka and the Commander Islands for the period 1979–2007. Examples are provided of the RCMs recorded in Kamchatka and the Commander Islands for the period 1997–2007 by the Kamchatka regional GPS network (KAMNET) set up by workers at the Kamchatka Branch of the RAS Geophysical Service (KB GS RAS) in collaboration with the Institute of Volcanology and Seismology of the Far East Division of the Russian Academy of Sciences to study the geodynamic processes that are occurring in the Kamchatka subduction zone. An interpretation of examples of recorded RCMs is given.  相似文献   

4.
There is a strong possibility that environmental change (whether climate or land use) will be manifest as changes in the size–frequency distribution of landslides. Here, evidence is presented for this from western Kyrgyzstan, Central Asia. Remote sensing and spatial analysis have been applied to map mass movements in the central part of the Maily‐Say Valley and to detect recent landslide activations. The evolution of landslide activity over the past 50 years has been analysed on the basis of pre‐existing landslide maps and new analyses of aerial photographs as well as Quickbird images. Five inventories were produced for the years 1962 (based on the existing map of 1962 and aerial photographs of 1962), 1984 (based on the existing map of 1977 and aerial photographs of 1984), 1996 (based on aerial photographs of 1996), 2002 (based on the existing map of 2003 and Quickbird imagery of 2002) and 2007 (based on Quickbird imagery of 2007). The geomorphologic features contained in the catalogues represent the landslide bodies observed from remote imagery of the corresponding year. Mapped landslides are generally considered as the result of a series of slope failure events. Size–frequency analyses applied to the five landslide inventories show that both the number and size of unstable slopes increased from 1962 (162 objects) to 2007 (208 objects) and the power‐law exponent decreased over time. This changing power‐law exponent may indicate that landslide‐related hazards are increasing. This tendency is documented in more detail for two active landslide zones, one in the main valley and one located to the west of it. Landslide detection methods were used to assist the evolution of slope instabilities. Choosing appropriate thresholds, the image subtraction method based on normalized difference vegetation index (NDVI) allowed accurate detection of new sliding activation in these two zones. This confirmed the results of the more extensive survey that there is a systematic shift in power law exponents and size–frequency distributions for Central Asian landslides. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

5.
On April 21, 2006 an earthquake with a magnitude of M s = 7.7 named Olyutor struck the Koryak Autonomous Region. It was the strongest earthquake for the entire period of historical and instrumental observations. The coordinates of the epicenter were 60.91° N, 166.98° E; the hypocenter’s depth was 12 km. For the efficient study of the earthquake, a team of scientists of the Institute of Volcanology and Seismology of the Far Eastern Branch of the Russian Academy of Sciences (RAS) was sent to the epicentral area. The article presents the results of studies of soil liquefaction in the settlement of Korf, which was the most affected during the Olyutor earthquake. The intensity of the earthquake in the settlement was 9 points. Numerous cracks in the soil were observed, sand volcanoes were formed, and there were numerous cases of sand and silt eruptions, subsidence, and flooding in the settlement. It was decided that the settlement was unfit for human habitation.  相似文献   

6.
The statistical characteristics of the intensity of VLF-LF radio signals transmitted from the midlatitude radio stations and recorded by the receiver at the Mikhnevo geophysical observatory (54.94°N, 37.73°E; Institute of Geosphere Dynamics, Russian Academy of Sciences) in 2007–2010 are analyzed. The experiments revealed strong variations in the intensity of radio signals during the deep solar minimum conditions, when the medium does not experience impacts from above associated with solar and geomagnetic activity. We relate the observed variations to the disturbances from below, which are caused by the meteorological and wave processes occurring in the lower atmosphere.  相似文献   

7.
 The 3.9- to 2.9-Ma Waianae Volcano is the older of two volcanoes making up the island of Oahu, Hawaii. Exposed on the volcanic edifice are tholeiitic shield lavas overlain by transitional and alkalic postshield lavas. The postshield "alkalic cap" consists of aphyric hawaiite of the Palehua Member of the Waianae Volcanics, overlain unconformably by a small volume of alkalic basalt of the Kolekole Volcanics. Kolekole Volcanics mantle erosional topography, including the uppermost slopes of the great Lualualei Valley on the lee side of the Waianae Range. Twenty new K–Ar dates, combined with magnetic polarity data and geologic relationships, constrain the ages of lavas of the Palehua member to 3.06–2.98 Ma and lavas of the Kolekole Volcanics to 2.97–2.90 Ma. The geochemical data and the nearly contemporaneous ages suggest that the Kolekole Volcanics do not represent a completely independent or separate volcanic event from earlier postshield activity; thus, the Kolekole Volcanics are reduced in rank, becoming the Kolekole Member of the Waianae Volcanics. Magmas of the Palehua and Kolekole Members have similar incompatible element ratios, and both suites show evidence for early crystallization of clinopyroxene consistent with evolution at high pressures below the edifice. However, lavas of the Kolekole Member are less fractionated and appear to have evolved at greater depths than the earlier Palehua hawaiites. Postshield primary magma compositions of the Palehua and Kolekole Members are consistent with formation by partial melting of mantle material of less than 5–10% relative to Waianae shield lavas. Within the section of Palehua Member lavas, an increase with respect to time of highly incompatible to moderately incompatible element ratios is consistent with a further decrease in partial melting by approximately 1–2%. This trend is reversed with the onset of eruption of Kolekole Member lavas, where an increase in extent of partial melting is indicated. The relatively short time interval between the eruption of Palehua and Kolekole Member lavas appears to date the initial formation of Lualualei Valley, which was accompanied by a marked change in magmatic conditions. We speculate that the mass-wasting event separating lavas of the Palehua and Kolekole Members may be related to the formation of a large submarine landslide west and southwest of Waianae Volcano. Enhanced decompression melting associated with removal of the equivalent volume of this landslide deposit from the edifice is more than sufficient to produce the modeled increase of 1–2% in extent of melting between the youngest Palehua magmas and the posterosional magmas of the Kolekole Member. The association between magmatic change and a giant landsliding event suggests that there may be a general relationship between large mass-wasting events and subsequent magmatism in Hawaiian volcano evolution. Received: 1 September 1996 / Accepted: 26 November 1996  相似文献   

8.
The results of microseismic monitoring in the adit of the neutrino laboratory (Institute of Nuclear Research, Russian Academy of Sciences) in the Elbrus Region are presented. Three-component computer recording was carried out in the frequency band 10–120 Hz with 5-second averaging of the amplitudes of vibrations. We consider the results of processing the data yielded by the monitoring in the adit during nine months since March 2008. The seismic field at the observation point is composed of three main contributions: the local earthquakes associated with two main fluid-magmatic sources, which are located nearby the adit; a slowly varying wave field, which is probably related to the same sources; and the industrial noise, namely, the vibrations caused by the traffic of carriages and a weak stationary background noise.  相似文献   

9.
Twenty-four years of AVHRR-derived sea surface temperature (SST) data (1985–2008) and 35 years of NOCS (V.2) in situ-based SST data (1973–2008) were used to investigate the decadal scale variability of this parameter in the Mediterranean Sea in relation to local air–sea interaction and large-scale atmospheric variability. Satellite and in situ-derived data indicate a strong eastward increasing sea surface warming trend from the early 1990s onwards. The satellite-derived mean annual warming rate is about 0.037°C year–1 for the whole basin, about 0.026°C year–1 for the western sub-basin and about 0.042°C year–1 for the eastern sub-basin over 1985–2008. NOCS-derived data indicate similar variability but with lower warming trends for both sub-basins over the same period. The long-term Mediterranean SST spatiotemporal variability is mainly associated with horizontal heat advection variations and an increasing warming of the Atlantic inflow. Analysis of SST and net heat flux inter-annual variations indicates a negative correlation, with the long-term SST increase, driving a net air–sea heat flux decrease in the Mediterranean Sea through a large increase in the latent heat loss. Empirical orthogonal function (EOF) analysis of the monthly average anomaly satellite-derived time series showed that the first EOF mode is associated with a long-term warming trend throughout the whole Mediterranean surface and it is highly correlated with both the Eastern Atlantic (EA) pattern and the Atlantic Multidecadal Oscillation (AMO) index. On the other hand, SST basin-average yearly anomaly and NAO variations show low and not statistically significant correlations of opposite sign for the eastern (negative correlation) and western (positive correlation) sub-basins. However, there seems to be a link between NAO and SST decadal-scale variations that is particularly evidenced in the second EOF mode of SST anomalies. NOCS SST time series show a significant SST rise in the western basin from 1973 to the late 1980s following a large warming of the inflowing surface Atlantic waters and a long-term increase of the NAO index, whereas SST slowly increased in the eastern basin. In the early 1990s, there is an abrupt change from a very high positive to a low NAO phase which coincides with a large change in the SST spatiotemporal variability pattern. This pronounced variability shift is followed by an acceleration of the warming rate in the Mediterranean Sea and a change in the direction (from westward to eastward) of its spatial increasing tendency.  相似文献   

10.
During 2007–2008, three CO2 flux surveys were performed on El Chichón volcanic lake, Chiapas, Mexico, with an additional survey in April 2008 covering the entire crater floor (including the lake). The mean CO2 flux calculated by sequential Gaussian simulation from the lake was 1,190 (March 2007), 730 (December 2007) and 1,134 g m−2 day−1 (April 2008) with total emission rates of 164 ± 9.5 (March 2007), 59 ± 2.5 (December 2007) and 109 ± 6.6 t day−1 (April 2008). The mean CO2 flux estimated from the entire crater floor area was 1,102 g m−2 day−1 for April 2008 with a total emission rate of 144 ± 5.9 t day−1. Significant change in CO2 flux was not detected during the period of survey, and the mapping of the CO2 flux highlighted lineaments reflecting the main local and regional tectonic patterns. The 3He/4He ratio (as high as 8.1 R A) for gases in the El Chichón crater is generally higher than those observed at the neighbouring Transmexican Volcanic Belt and the Central American Volcanic Arc. The CO2/3He ratios for the high 3He/4He gases tend to have the MORB-like values (1.41 × 109), and the CO2/3He ratios for the lower 3He/4He gases fall within the range for the arc-type gases. The high 3He/4He ratios, the MORB-like CO2/3He ratios for the high 3He/4He gases and high proportion of MORB-CO2 (M = 25 ±15%) at El Chichón indicate a greater depth for the generation of magma when compared to typical arc volcanoes.  相似文献   

11.
On September 4, 2007, after 25 years of effusive natrocarbonatite eruptions, the eruptive activity of Oldoinyo Lengai (OL), N Tanzania, changed abruptly to episodic explosive eruptions. This transition was preceded by a voluminous lava eruption in March 2006, a year of quiescence, resumption of natrocarbonatite eruptions in June 2007, and a volcano-tectonic earthquake swarm in July 2007. Despite the lack of ground-based monitoring, the evolution in OL eruption dynamics is documented based on the available field observations, ASTER and MODIS satellite images, and almost-daily photos provided by local pilots. Satellite data enabled identification of a phase of voluminous lava effusion in the 2 weeks prior to the onset of explosive eruptions. After the onset, the activity varied from 100 m high ash jets to 2–15 km high violent, steady or unsteady, eruption columns dispersing ash to 100 km distance. The explosive eruptions built up a ∼400 m wide, ∼75 m high intra-crater pyroclastic cone. Time series data for eruption column height show distinct peaks at the end of September 2007 and February 2008, the latter being associated with the first pyroclastic flows to be documented at OL. Chemical analyses of the erupted products, presented in a companion paper (Keller et al. 2010), show that the 2007–2008 explosive eruptions are associated with an undersaturated carbonated silicate melt. This new phase of explosive eruptions provides constraints on the factors causing the transition from natrocarbonatite effusive eruptions to explosive eruptions of carbonated nephelinite magma, observed repetitively in the last 100 years at OL.  相似文献   

12.
On the basis of measurements of the intensity of 1.58-μm emissions of the Infrared Atmospheric System of molecular oxygen (IRAO2) conducted at the Zvenigorod scientific station of the Institute of Atmospheric Physics of the Russian Academy of Sciences (φ = 55.7°N, λ = 36.8°E), seasonal variations are estimated for various solar zenith angles. Their amplitude has the maximum value at the solar zenith angles χ S ∼ 105–110°. It decreases at χ S ∼ 125–130° and tends to zero at χ S ∼ 80–85°. The comparison of currently measured values of the 1.58-μm emission intensity of the Infrared Atmospheric System of molecular oxygen with published data on the intensity of this emission obtained in 1961–1966 reveals their decrease over approximately 50 years. This fact is in good agreement with similar behavior of the emission intensity of atomic oxygen (557.7 nm) over the period considered.  相似文献   

13.
The aquatic vegetation of ?í?ov Lake in the Danube floodplain, which is listed in the Ramsar Convention, was investigated to address three main questions: (1) how have landscape composition and the structures of the lake and its buffer zone changed from the mid-20th century; (2) how have species richness and the abundance of the aquatic macrophyte assemblage in this lake ecosystem changed over the last 34 years; and (3) which landscape metrics can best explain these temporal changes for floating-leaved macrophytes? Two methodological approaches, remote sensing and botanical field surveys, were applied. Historical (1949, 1970, 1990) and contemporary (2006) aerial photographs were analysed to determine land cover. Landscape configuration and structure were analysed using eight landscape metrics selected in advance to measure spatio-temporal changes and the fragmentation of the lake ecosystem and its corresponding buffer zone. The species diversity, abundance and distribution of true aquatic macrophytes were surveyed eleven times in five survey stretches between 1973 and 2007.At the landscape level, a decrease in the area covered by floating-leaved macrophytes, as well as an increase in open water surface and fragmentation of the land cover classes in the lake ecosystem, were recorded from 1949 to 2006. Overall, 30 true aquatic macrophytes were found from 1973 to 2007. Species richness did not change considerably, but the abundance of aquatic species fluctuated over the years. Three groups of true aquatic vegetation, based on common structural characteristics, were found in 1973–1983, 1989–2002, and 2004–2007 over the last 34 years. The landscape metrics NP, PD, LPI, and SHDI, which all express patterns of landscape fragmentation mostly indicate temporal changes in floating-leaved macrophytes.  相似文献   

14.
The changes in the hardware/software system for seismic monitoring as applied to the conditions of the adit of the Institute of Nuclear Research, Russian Academy of Sciences, in the Elbrus region are described. A three-component computer recording within the frequency range of 10–120 Hz was carried out with the averaging of vibration amplitudes on an interval of 5 s. The results of data processing for the first six months of monitoring carried out starting from March 2008 in the adit are considered. The seismic field in the observation site has three main components: local earthquakes related to the two main magmatic fluid sources located nearby; a slowly changing wave field, possibly related to the same sources; and technogenic noise, in particular, vibration caused by the trolleys in motion, and a weak stationary background.  相似文献   

15.
Lidar observations during 2007–2008 in Kamchatka revealed aerosol layers in the upper stratosphere at heights of 35–50 km and in the mesosphere at heights of 60–75 km. It is well known that forces of gas-kinetic nature, i.e., photophoretic forces, act on aerosol particles that absorb solar radiation and terrestrial IR radiation; these forces can counteract the gravitational force and even lead to the levitation of these particles at particular heights. The accumulation of particles at these heights may lead to the formation of aerosol layers. We calculated these forces for the conditions of lidar observations in Kamchatka. Aerosol layers were observed at heights where particle levitation can occur. Thus, the stratospheric and mesospheric aerosol layers, detected at heights of 30–50 and 60–75 km, respectively, may be due to the effect of the photophoretic force on aerosol particles.  相似文献   

16.
The aim of this study was to apply, verify and compare a multiple logistic regression model for landslide susceptibility analysis in three Korean study areas using a geographic information system (GIS). Landslide locations were identified by interpreting aerial photographs, satellite images and a field survey. Maps of the topography, soil type, forest cover, lineaments and land cover were constructed from the spatial data sets. The 14 factors that influence landslide occurrence were extracted from the database and the logistic regression coefficient of each factor was computed. Landslide susceptibility maps were drawn for these three areas using logistic regression coefficients derived not only from the data for that area but also using those for each of the other two areas (nine maps in all) as a cross‐check of method validity. For verification, the results of the analyses were compared with actual landslide locations. Among the nine cases, the Janghung exercise using the logistic formula and the coefficient for Janghung had the greatest accuracy (88·44%), whereas Janghung results, when considered by the logistic formula and the coefficient for Boeun, had the least accuracy (74·16%). Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

17.
Kick 'em Jenny volcano is the only known active submarine volcano in the Lesser Antilles. It lies within a horseshoe-shaped structure open to the west northwest, toward the deep Grenada Basin. A detailed bathymetric survey of the basin slope at Kick 'em Jenny and resulting high-resolution digital elevation model allowed the identification of a major submarine landslide deposit. This deposit is thought to result from a single sector collapse event at Kick 'em Jenny and to be linked to the formation of the horseshoe-shaped structure. We estimated the volume and the leading-edge runout of the landslide to be ca. 4.4 km3 and 14 km, respectively. We modelled a sector collapse event of a proto Kick 'em Jenny volcano using VolcFlow, a finite difference code based on depth-integrated mass and momentum equations. Our models show that the landslide can be simulated by either a Coulomb-type rheology with low basal friction angles (5.5°–6.5°) and a significant internal friction angle (above 17.5°) or, with better results, by a Bingham rheology with low Bingham kinematic viscosity (0 < ν B < 30 m2/s) and high shear strength (130 < γ ≤ 180 m2/s2). The models and the short runout distance suggest that the landslide travelled as a stiff cohesive flow affected by minimal granular disaggregation and slumping on a non-lubricated surface. The main submarine landslide deposit can therefore be considered as a submarine mass slide deposit that behaved like a slump.  相似文献   

18.
The contribution of atmospheric pressure and local wind to sea level variability at Goa (West coast of India) for the period 2007–2008 is investigated. Sea level data from a tide gauge are compared with measured local surface meteorological as well as oceanographic data. Multilinear regression analysis is used to resolve the dependence of sea level on various forcing parameters. The multilinear regression analysis performed over approx. 2-year data shows that the local surface meteorological data and water temperature account for the sea level variability only up to 6%. The accounted sea level variability increases to 25%, when the local wind and the surface currents obtained from satellite altimetry in the near vicinity of the study area are incorporated in the regression analysis. The contribution of local wind increases substantially when the regression is performed over a 2-month duration, and it is variable within the year. During the summer monsoon season (May–September), the sea level variability attributable to wind is up to 47% and 75%, respectively, for 2007 and 2008; however, it reduces to <20% during the winter monsoon (November–February) season. A significant part of the variability observed in sea level remains unaccounted for and is attributed to remote forcing.  相似文献   

19.
In this study, the spatio-temporal evolution of Yellowstone deformation between 1992 and 2009 is monitored using interferometric synthetic aperture radar (InSAR) data acquired by the European Remote-Sensing Satellites (ERS-1 and ERS-2) and the Environmental Satellite (ENVISAT). These data are combined with continuous global positioning system (GPS) measurements to identify four discrete episodes of caldera subsidence and uplift, these episodes are: 1992–1995 (subsidence of 2.7 cm/year), 1996–2000 (subsidence of 0.5 cm/year, with local uplift of 1.7 cm/year at Norris), 2000–2004 (subsidence of 0.7 cm/year, with local uplift of 0.6 cm/year at Norris), and 2004–2009 (uplift of 3–8 cm/year, with local subsidence of 1–4 cm/year at Norris). We construct the full three-dimensional velocity field of Yellowstone deformation for 2005–2006 from ascending and descending ENVISAT orbits. The InSAR three-dimensional velocity field and three-component GPS measurements indicate that the majority of the observed deformation (3–8 cm/year) across the Yellowstone caldera and near Norris Geyser Basin (NGB) occurred in the vertical direction between the summers of 2005 and 2006. During this time, significant lateral displacements of 3–7 cm/year also occurred in the east–west direction at the southeastern and western rims of the Yellowstone caldera and in the area between Hebgen Lake and NGB. Minor north–south displacements of about 0.2 cm/year also occurred, however, in the southwestern section of the caldera and near Yellowstone Lake during the same period. The calculated three-dimensional velocity field for 2005–2006 implies the existence of two pressure-point sources, beneath the two structural resurgent domes in the Yellowstone caldera, connected by a planar conduit, rather than a single, large sill as proposed in previous studies. Furthermore, no measurable displacements occurred along any fault zone across the caldera during the entire period of observation (1992–2009). Therefore, we infer that magmatic and hydrothermal processes beneath the Yellowstone caldera and NGB were the main sources of deformation.  相似文献   

20.
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