Crue éclair de juillet 1996 dans la région du Saguenay (Québec). 2. Impacts sur les sédiments et le biote de la baie des Ha! Ha! et du fjord du Saguenay

1999 ◽  
Vol 56 (11) ◽  
pp. 2136-2147 ◽  
Author(s):  
Émilien Pelletier ◽  
Bruno Deflandre ◽  
Christian Nozais ◽  
Guglielmo Tita ◽  
Gaston Desrosiers ◽  
...  
Keyword(s):  
Flash Flood ◽  
Biological Indicators ◽  
Average Density ◽  
Benthic Habitat ◽  
Sediment Layer ◽  
Pioneer Species ◽  
The North ◽  
Geological Processes ◽  
Saguenay Fjord ◽  
Interstitial Waters

Several million tons of sediments and various debris were transported to the north arm of the Saguenay Fjord and the Baie des Ha! Ha! following the torrential rains and accompanying flash flood of July 1996 in the Saguenay region (Québec). The flood deposits covered the indigenous sediments and buried the benthic community. The objective of this work is to determine the best chemical and biological indicators of the changes that occurred in the benthic habitat of the fjord. The new sediment layer is poor in organic matter but rich in detrital carbonates and contains low mercury and lead concentrations reflecting the absence of industrial contamination. Ongoing geological processes leading to the re-establishment of steady-state conditions were evidenced by measurements of porosity, redox potential (Eh), and salinity of interstitial waters taken a few weeks and a few months after the events. The meiofauna were severely affected with a massive reduction of the average density of organisms relative to values recorded before the flood, but recolonisation was already in progress 1 year after the flood. Important losses of macrobenthic species were recorded in 1997 relative to 1996. However, the abundance and the diversity of the polycheate taxa were higher in 1997, indicating a recolonisation of the new sediment layer by pioneer species.

Crue éclair de juillet 1996 dans la région du Saguenay (Québec). 1. Impacts sur la colonne d'eau de la baie des Ha! Ha! et du fjord du Saguenay

1999 ◽  
Vol 56 (11) ◽  
pp. 2120-2135 ◽  
Author(s):  
Émilien Pelletier ◽  
Behzad Mostajir ◽  
Suzanne Roy ◽  
Michel Gosselin ◽  
Yves Gratton ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Column ◽  
Flash Flood ◽  
Physiological State ◽  
Biological Indicators ◽  
Suspended Particles ◽  
Zooplankton Species ◽  
Pelagic Ecosystem ◽  
Physical Chemical ◽  
Saguenay Fjord

A flash flood, which occurred in July 1996 in the Saguenay area (Quebec), transported millions of tons of sediment to the upstream section of the Saguenay Fjord and the Baie des Ha! Ha! in a few days. This first article reports the physical, chemical, and biological observations obtained for the water column in September 1996 and August 1997 and attempts to define indicators that can adequately characterize the effects of the flood on the water column. The chemical composition, the abundance, and the distribution of suspended particles clearly show the influence of the flood on the composition of particles in the water column of the bay and the fjord 2 months and even 1 year after the flood. However, biological indicators such as the abundance and the distribution of phytoplankton and zooplankton species determined in September 1996 are only slightly different between the Bay and the Fjord and show little difference with preflood data. The zooplankton physiological state appears to be a very good indicator of the health of the whole pelagic ecosystem.

Engineering-Geological Studies Of The Territory, Soils Of Foundation And Foundations Of The Architectural Monument Of The "Melnikov’s House" In Moscow

2019 ◽  
pp. 41-51
Keyword(s):  
Working Condition ◽  
Overlying Water ◽  
North East ◽  
The North ◽  
Geological Processes ◽  
Architectural Monument ◽  
Geological Conditions ◽  
Zone Of Influence ◽  
Complex Engineering ◽  
Building Engineering

On the basis of engineering and design surveys of the building, engineering-geological and geophysical studies of the soils of the territory conducted by the article authors, as well as with due regard for the results of studies conducted on this territory by other authors, the features of the foundations, soils of their foundation and engineering-geological conditions of the territory of the Melnikov House are established. It is shown that the Melnikov house is located under complex engineering-geological conditions on the territory of high geological risk, in the zone of influence of tectonic disturbance. To the North of the area there is a zone of intersection of the observed disturbance with a larger disturbance that can have an impact on geological processes. To the North-East of the site of the Melnikov House, a sharp immersion of the roof of carbon deposits was revealed. It promotes groundwater seepage into limestone of the carbonate strata from overlying water-bearing sands and activation of processes of suffusion removal and sinkhole phenomena of the soil. The surveyed area is assessed as potentially karst-hazardous and adjacent to it from the North-East territory as karst-dangerous. In this regard any construction on the adjacent territory can provoke activation of sinkhole phenomena on the surface. The foundations of the building are basically in working condition. Existing defects can be eliminated during repair. The foundation soils mainly have sufficient bearing capacity. Areas of the base with bulk soil can be reinforced. However, when developing a project for the reconstruction of the building and its territory, it should be taken into account that the design of the Melnikov House does not provide for its operation on the loads at the formation of sinkholes.

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

Sediment Thickness and Moho Depth Beneath Western Indonesian Region From Teleseismic Receiver Function

2021 ◽  
Author(s):  
Syaiful Bahri ◽  
Wiwit Suryanto ◽  
Drajat Ngadmanto
Keyword(s):  
Shear Wave ◽  
Shear Wave Velocity ◽  
Receiver Function ◽  
Velocity Model ◽  
Moho Depth ◽  
Sediment Layer ◽  
The North ◽  
East Kalimantan ◽  
Crust Layer ◽  
Teleseismic Receiver Function

Abstract The Earth's crust layer and sediment in Western Indonesia has been studied using the inversion of teleseismic receiver function from BMKG’s seismic network. Earthquake events were analyzed in this study with a moment magnitude greater than 6.0 with epicentral distances of 30° to 90°. A total of 60 earthquake events were observed and recorded by 91 stations around the study area. Furthermore, an inversion process was carried out using the initial velocity model from the modification of the AK135f velocity model to obtain the shear wave velocity structure below each stations. The velocity model from the azimuthally stacked vertical receiver function showed that the sediment layer had a relatively medium shear wave velocity value with an average of 2.1 km/s, while the crust layer had 4.60 km/s. The sedimentary layer thickness in this region also varies between 2 km to 10 km. A relatively thick sediment layer of about 8 km to 10 km was observed in two locations, in East Kalimantan associated with the Kutai Basin and Northern part of Sumatera in the North Sumatera Basin, a two major oil producer basinal area in Indonesia. The Moho discontinuity was also found at depths that vary between 16 km to 50 km. In addition, the most shallow Moho depth is 16 km below the North Kalimantan and North part of West Java, while the deeper Moho depth of 50 km is located below East Kalimantan, Central Kalimantan, North Sumatera and South Sumatera.

Effects of 2017 Early Flash Flooding on Agriculture in Haor Areas of Sunamganj

2021 ◽  
Vol 12 (1-2) ◽  
pp. 117-125
Author(s):  
S Mondal ◽  
L Akter ◽  
HJ Hiya ◽  
MA Farukh
Keyword(s):  
Agricultural Production ◽  
Flash Flood ◽  
Eastern Region ◽  
Fish Production ◽  
Flood Events ◽  
Flash Flooding ◽  
The North ◽  
North Eastern ◽  
Boro Rice

The Sunamganj district is covered by major Haor systems in the north-eastern region of Bangladesh. Flash flood is the most commonly occurring water related disaster in the Haor areas. During the flash flood it is very common that people lost their primary agricultural productions which are the only source of their livelihood. The present study focuses on the effects of 2017 early flash flooding on rice and fish production of Sunamganj Haor areas. The flood caused enormous damage to agriculture such as rice especially Boro rice and fish production on which the Haor dwellers rely upon for their livelihood. The total affected land of Boro rice cultivation in Haors of Sunamganj was 149,224 hectare and the total amount of damaged rice was 393,855 metric ton (MT). The total number of affected farmers was 315,084. The early flash flood also affects the quality of Haor water which caused the death of fishes. The total amount of damaged fish was 49.75 MT and the loss was 158.70 lakh taka. The total number of affected fishermen was 44,445. This findings could be very useful for the environmental scientists to predict the probable future effects on agricultural production due to early flash flood events in Sunamganj Haors areas. Environ. Sci. & Natural Resources, 12(1&2): 117-125, 2019

THE ROLE OF TECHNOGENIC IMPACT IN THE DEVELOPMENT OF DANGEROUS GEOLOGICAL PROCESSES IN THE MOUNTAIN REGIONS OF THE NORTHERN CAUCASUS

2021 ◽  
Vol 43 (4) ◽  
pp. 437-450
Author(s):  
Irina Malneva ◽  
Nina Kononova ◽  
Muhtar Hadzhiev
Keyword(s):  
Negative Impact ◽  
Climatic Conditions ◽  
Northern Caucasus ◽  
North Caucasus ◽  
Mountainous Regions ◽  
Technogenic Impact ◽  
The North ◽  
Geological Processes ◽  
Rock Formations ◽  
Operational Forecasts

The article presents an assessment of technogenic impact on the development of hazardous geological processes in the mountainous regions of the Northern Caucasus in the current century. Technogenic impact is determined by the stability of rock formations that make up the Krasnodar Territory, Kabardino-Balkaria, and North Ossetia relative to the impacts of other forces. It is also noted that the activity of hazardous geological processes is largely determined by the interaction of climatic conditions, which determine their speed, and technogenesis. Examples of problematic territories of the North Caucasus are given. To assess climatic changes and major catastrophes, a typology of atmospheric circulation in the Northern Hemisphere was developed under the leadership of B.L. Dzerdzeevsky. Typification materials from the period between 1899 and 2018 are posted in the public domain, at www.atmospheric-circulation.ru. The largest catastrophes, in which landslides and mudflows became more active, and the interaction of natural and man-made factors in these disasters are considered.Hazardous geological processes can disrupt the sustainable development of individual regions with their negative impact on the environment. The assessment of their danger is therefore of special current relevance. The article considers the possibility of predicting catastrophes associated with these processes. Long-term forecasts of landslides, mudflows and other processes continue to be important. The methodology of such forecasting was previously developed in sufficient detail. The greatest importance is assigned to operational forecasts that will make it possible to warn of possible danger hours or even days ahead.

Geology and Ages of the Islands

2002 ◽  
Author(s):  
Ana Luisa Carreño ◽  
Javier Helenes
Keyword(s):  
Sea Level ◽  
Gulf Of California ◽  
Baja California ◽  
Distribution Patterns ◽  
Complete Analysis ◽  
Interglacial Period ◽  
North American Continent ◽  
The North ◽  
Geological Processes ◽  
Continental Source

Before middle Miocene times, Baja California was attached to the rest of the North American continent. Consequently, most of the terrestrial fauna and flora of the peninsula had its origins in mainland Mexico. However, the separation of the peninsula and its northwestward displacement resulted in a variety of distribution patterns, isolations, extinctions, origins and ultimate evolution of fauna and flora in several ways. The islands in the Gulf of California have been colonized by species from Baja California and mainland Mexico. Some workers (Soulé and Sloan 1966; Wilcox 1978) consider that many of these islands originated as landbridges. Geographically, most of the islands are closer to the peninsula than to the mainland. Therefore, it has been assumed that the Baja California Peninsula was the origin of most of the organisms inhabiting them (Murphy 1983). Islands separated by depths of 110 m or less from the peninsula or mainland Mexico apparently owe their current insular existence to a rise in sea level during the current interglacial period (Soulé and Sloan 1966). In contrast, little information exists for deep-water islands. Any complete analysis of the distribution and origin of several organic groups inhabiting the Gulf of California islands should involve the consideration of several contrasting models arguing in favor of or against the equilibrium theory (MacArthur and Wilson 1967). In any model, one of the most important features to consider is the relationship between the species inhabiting the gulf islands and the physical and geological processes of formation of the islands, as well as their age, size, and distance from either the peninsula or the mainland. Understanding colonization, migration, and distribution, particularly in some groups, requires information on whether a particular island was ever connected to a continental source. For example, to explain some characteristics of the populations of any island, which presumably had a recent (<10,000-15,000 years) connection to a continental source, it is necessary to evaluate the coastal erosion or the relative rise in the sea level. These factors might contribute to effectively isolating an insular habit or to forming landbridges.

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