The Bontău Volcano, Apuseni Mts. (Romania), source for numerous debris avalanche deposits

2021 ◽  
Author(s):  
Gabriel Corneliu Stefan ◽  
Viorel Mirea ◽  
Ioan Seghedi
Keyword(s):  
Debris Avalanche ◽  
Volcanic Area ◽  
Field Observations ◽  
Vertical Movements ◽  
Research And Innovation ◽  
Debris Avalanches ◽  
Isotopic Analyses ◽  
Surrounding Areas ◽  
Avalanche Generation ◽  
Volcaniclastic Deposits

<p>The Neogene volcanism in the western part of Romania is confined to the Apuseni Mountains and surrounding areas. The largest volcanic area is mostly developed in the WNW-ESE oriented, ca. 120 km in length Zărand-Brad-Zlatna Basin.</p><p>The Bontău Volcano (Seghedi et al., 2010) is located inside the western part of the Zărand-Brad-Zlatna Basin and it is strongly affected by erosional processes, being crossed in its northern part, from east to west, by the Crișul Alb River.</p><p>The Bontău Volcano is known to be active roughly between 14-10 Ma (according to the available K/Ar data) and it has been characterized as a composite or stratovolcano volcano associated with dome complexes, built by calc-alkaline andesitic lavas and pyroclastic deposits (andesite to basaltic andesite). The long-lasting volcanism developed in the Bontău area has a complex build up stages that we recently have found were interrupted by a series of destructive failure events. Several important volcanic collapses of the volcanic edifice took place producing large volcanic debris avalanches followed by numerous debris flows which produced various secondary volcaniclastic deposits that can be observed in different places all around the Bontău volcano. The debris avalanches deposits have not yet been known up to this study. The distribution of the debris avalanche deposits and associated volcaniclastic deposits is the main target of this study. In order to reconstruct Bontău Volcano activity and reconstruct its original morphology we done field observations and sampled the main lithologies to perform petrographic observations and geochemical and isotopic analyses (for the main lithologies).</p><p>During our field observations we tried to identify the relationships between debris avalanche deposits and older volcanic bodies (lavas, domes, volcaniclastic). One main important remark is related with the presence of several small basins at the margin of the volcano consisting of a succession of thin planar and cross-bedded sandstone in an alternation of coarse and fine layers associated with discontinuous lapilli trains (including pumices); The deposits are poorly to moderately sorted; with low angle cross lamination in lenses or pockets. Such deposits, as closely associate with debris avalanche deposits have been interpreted as small intra-hummocky basins formed after debris avalanche generation; they are mostly situated at the margins of the volcano.</p><p>The presence of multiple debris avalanche deposits can be connected with volcano growing in an extensional environment. We may assume that the long-lived Miocene rift graben system of the Zărand-Brad-Zlatna Basin experienced numerous changes in the fracture propagation and vertical movements that promoted repeated dyke intrusion and facilitated generation of numerous debris avalanches.</p><p>Acknowledgements: This work was supported by a grant of the of Ministry of Research and Innovation, CNCS – UEFISCDI, project number PN-III-P4-ID-PCCF-2016-4-0014, within PNCDI III.</p>

Soil history and debris avalanche deposits along the Illawarra scarpland

Soil Research ◽  
1963 ◽  
Vol 1 (2) ◽  
pp. 223 ◽  
Author(s):  
PH Walker
Keyword(s):  
Debris Avalanche ◽  
Climatic Conditions ◽  
Phase Instability ◽  
Alternate Form ◽  
The Past ◽  
Weathered Zone ◽  
Debris Avalanches ◽  
History Of

Two major periods of avalanching have occurred along the Illawarra scarpland. The older, the Scarborough formation, is characterized by a very thick, acid, weathered zone, similar to the lower mottled horizons of laterite profiles. The younger, Keira formation, has relatively shallow red and yellow earth profiles developed in it. Although its profile of deep weathering has some features in common with laterite, the Scarborough formation is not part of the general laterite surface, but represents a separate period of prolonged stability and weathering. The debris-avalanches are thought to have been deposited during excessively wet climatic conditions in the past, and they represent an alternate form of instability compared with the dry phase instability proposed for the K-cycle history of milder hillslope terrain near Nowra.

scholarly journals Characteristics of debris avalanche deposits inferred from source volume estimate and hummock morphology around Mt. Erciyes, central Turkey

2018 ◽  
Vol 18 (2) ◽  
pp. 429-444 ◽  
Author(s):  
Yuichi S. Hayakawa ◽  
Hidetsugu Yoshida ◽  
Hiroyuki Obanawa ◽  
Ryutaro Naruhashi ◽  
Koji Okumura ◽  
...  
Keyword(s):  
Cross Sections ◽  
Land Surface ◽  
Flow Direction ◽  
Debris Avalanche ◽  
Caldera Wall ◽  
High Definition ◽  
Sector Collapse ◽  
Volume Estimate ◽  
Debris Avalanches ◽  
Central Turkey

Abstract. Debris avalanches caused by volcano sector collapse often form characteristic depositional landforms such as hummocks. Sedimentological and geomorphological analyses of debris avalanche deposits (DADs) are crucial to clarify the size, mechanisms, and emplacement of debris avalanches. We describe the morphology of hummocks on the northeastern flank of Mt. Erciyes in Kayseri, central Turkey, likely formed in the late Pleistocene. Using a remotely piloted aircraft system (RPAS) and the structure-from-motion and multi-view stereo (SfM–MVS) photogrammetry, we obtained high-definition digital elevation model (DEM) and orthorectified images of the hummocks to investigate their geometric features. We estimated the source volume of the DAD by reconstructing the topography of the volcano edifice using a satellite-based DEM. We examined the topographic cross sections based on the slopes around the scar regarded as remnant topography. Spatial distribution of hummocks is anomalously concentrated at a certain distance from the source, unlike those that follow the distance–size relationship. The high-definition land surface data by RPAS and SfM revealed that many of the hummocks are aligned toward the flow direction of the debris avalanche, suggesting that the extensional regime of the debris avalanche was dominant. However, some displaced hummocks were also found, indicating that the compressional regime of the flow contributed to the formation of hummocks. These indicate that the flow and emplacement of the avalanche were constrained by the topography. The existing caldera wall forced the initial eastward flow to move northward, and the north-side caldera wall forced the flow into the narrow and steepened outlet valley where the sliding debris underwent a compressional regime, and out into the unconfined terrain where the debris was most likely emplaced on an extensional regime. Also, the estimated volume of 12–15 × 108 m3 gives a mean thickness of 60–75 m, which is much deeper than the reported cases of other DADs. This suggests that the debris avalanche must have flowed further downstream and beyond the current DAD extent. Assessments of the DAD incorporating the topographic constraints can provide further insights into the risk and mitigation of potential disasters in the study area.

Peru earthquake of May 31, 1970; engineering geology observations

1971 ◽  
Vol 61 (3) ◽  
pp. 511-533 ◽  
Author(s):  
Lloyd S. Cluff
Keyword(s):  
Ground Motion ◽  
Engineering Geology ◽  
Debris Avalanche ◽  
Soil Conditions ◽  
Average Speed ◽  
The North ◽  
The Poor ◽  
Debris Avalanches ◽  
Field Evidence ◽  
Secondary Factor

abstract At 3:23 p.m. local time, on May 31, 1970, an earthquake of magnitude 7 ¾; occurred approximately 15 miles off the coast of Peru, west of Chimbote. It is estimated that the earthquake took the lives of 70,000 people, caused 50,000 injuries, destroyed roughly 200,000 homes and buildings, and left approximately 800,000 people homeless. Within the affected region, roughly 40,000 square miles, many villages were almost totally destroyed and several were swept away. The single, most devastating event was the large debris avalanche that originated from the north peak of Huascaran, falling 12,000 ft and traveling 7 miles at an average speed of roughly 200 miles per hour to destroy the villages of Yungay and Ranrahirca. Field evidence strongly suggests that the area near Yungay and Ranrahirca will continue to be overridden by future debris avalanches. Damage resulting from vibrational effects was severe. The most intense vibrational damage occurred along the coast at Chimbote and Casma where most houses and buildings of adobe construction were destroyed or severely damage. Severe vibrational damage also occurred in cities and villages located in the Santa Valley at epicentral distances ranging from 60 to 100 miles inland. The single, most important factor contributing to the massive damage from ground motion was the poor adobe construction. The influence of the underlying geological and soil conditions was an important secondary factor.

Debris avalanche impoundments of Squamish River, Mount Cayley area, southwestern British Columbia

1991 ◽  
Vol 28 (9) ◽  
pp. 1375-1385 ◽  
Author(s):  
Gregory R. Brooks ◽  
Edward J. Hickin
Keyword(s):  
British Columbia ◽  
Depositional Environment ◽  
Debris Avalanche ◽  
Low Energy ◽  
Fluvial Deposits ◽  
Debris Avalanches ◽  
Lower Terrace ◽  
Terrace Deposit

Squamish River has been impounded temporarily by debris avalanches from Mount Cayley on numerous occasions. Evidence of these impoundments comes from backwater deposits and also from a cluster of in situ stumps protruding from a bar along Squamish River. Backwater deposits consist of both lacustrine and fluvial deposits that have formed within the low-energy depositional environment created by a river impoundment. Three main backwater deposits occur in the study area. The fan toe deposit is ~14 m thick and represents a single impoundment of Squamish River that likely formed behind a large ~4800 BP debris avalanche. In situ ~3200 BP stumps along Squamish River probably were killed by a river impoundment due to a debris avalanche. The upper terrace backwater deposit is ~6 m thick and forms an aggradational terrace along Squamish River which probably accumulated behind an ~1100 BP debris avalanche. The lower terrace deposit also forms an aggradational terrace along Squamish River but represents four or possibly five separate impoundments. These occurred between ~1100 BP and 1955 AD, and it seems likely that one of the deposits relates to an ~500 BP debris avalanche. Seven or eight Holocene impoundments of Squamish River have been identified in the study area.

scholarly journals Differential vertical movements in the eastern North Sea area from 3-D thermo-mechanical finite elemental modelling

2002 ◽  
Vol 49 ◽  
pp. 119-128
Author(s):  
Lykke Gemmer ◽  
Søren B. Nielsen ◽  
Holger Lykke Andersen
Keyword(s):  
Stress Field ◽  
North Sea ◽  
Late Cretaceous ◽  
Thermal Structure ◽  
Three Dimensional ◽  
Element Model ◽  
Vertical Movements ◽  
Surrounding Areas ◽  
Sea Area ◽  
Weak Zones

The response of a heterogeneous lithosphere to a compressional stress field is studied using a three-dimensional thermo-mechanical finite element model. Weak zones in the lithosphere thicken and act as loads that pull down the lithosphere in regions around the weak zones. Strong zones are subjected to less lithospheric thickening than the surroundings and produce surface depressions and uplift in the surrounding areas. The model is used to study the Late Cretaceous and Paleocene differential vertical movements in the eastern North Sea area. The Sorgenfrei-Tornquist Zone is assumed to be a pre-existing weak crustal zone, which inverts during compression and produces marginal basins by loading the lithosphere. The area of the Silkeborg Gravity High is an example of a pre-existing strong crustal zone which subsides during compression. Moho topography in the area gives rise to lateral strength variations, which result in surface uplift where Moho is deep and subsidence where Moho is shallow. These effects, together with the lateral variations of the thermal structure and the stress field, determine the overall Late Cretaceous-Paleocene distribution of vertical movements of the area. This has implications for the pattern of erosion, sediment transport and the distribution of sediment facies.

scholarly journals Perkembangan Perumahan Publik di Negeri Sakura: Studi Kasus pada Perumahan di Tokyo dan Sekitarnya

2011 ◽  
Vol 2 (2) ◽  
pp. 1152
Author(s):  
Nina Nurdiani
Keyword(s):  
Public Housing ◽  
Urban Areas ◽  
Local Culture ◽  
Field Observations ◽  
Literature Study ◽  
Japanese People ◽  
Residential Design ◽  
Descriptive Approach ◽  
Surrounding Areas ◽  
The City

Japan currently has been successful to provide housing for low to high-income people in urban areas. Almost everyone in Japan can access their homes, either public housing or private one, depending on the level of their welfare status. The study discusses about development of public housing in Japan and why the Japanese people can accept the design of the vertical housing built by their government. The study is conducted with descriptive approach through literature study and field observations in the city of Tokyo and its surrounding areas to provide knowledge about the development of public housing in Japan started from traditional residential and then developed into a modern residential horizontally and vertically according to the needs of his hometown community. Despite of the development from time to time, the design of residence still considers the local culture of Japan. So the Japanese people can receive residential design, although it is developed into vertical housing. This study is expected to give inputs for the Indonesian government as an effort to achieve the successful provision of public housing in Indonesia. 

The role of sedimentology in the mobility of debris avalanches: Evidence from their deposits and granular flow experiments

2021 ◽  
Author(s):  
Symeon Makris ◽  
Irene Manzella ◽  
Paul Cole ◽  
Matteo Roverato
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Granular Flows ◽  
High Water ◽  
Debris Avalanche ◽  
High Water Content ◽  
Sediment Size ◽  
Debris Avalanches ◽  
Volcanic Debris

<p>Debris avalanches and lahars are among the most destructive and hazardous mass flows in volcanic environments making them important to understand from a hazard assessment perspective. Sedimentological characteristics of their deposits are important for assessing their propagation and emplacement mechanisms. Here, we compare the sedimentology of nine volcanic debris avalanches and eight lahars, by the descriptive statistics: median grain size, sand, gravel and finer particle proportion, skewness, and sorting.</p><p>Results suggest that lahars and debris avalanches diverge in their grain size distribution evolution during propagation, even when sourced from the same material. Increasing bimodality, evolution to negative skewness, with decreasing sediment size, accompanied by very poor sorting suggest comminution of particles due to particle-particle interactions in debris avalanches. Instead, preferential deposition of the coarsest particles and improved sorting suggest that the decrease in grain size of lahars is the result of debulking. The divergence is mainly caused by the high water content in lahars, which introduce different processes during propagation. This suggests, in agreement with previous studies, that debris avalanches can be considered as dense granular flows where the effect of inertial collisions of solid fragments are more important than fluid effects.</p><p>Present findings and previous sedimentological studies suggest that both volcanic and non-volcanic debris avalanches exhibit bimodal grain-size distributions, at least locally, in areas of high shear accommodation. Following these results, an experimental campaign has been carried out to test the effect of bimodality on the propagation of granular flows. These experiments are flows of bidisperse granular material on an initial inclined plane, with a horizontal accumulation surface at the bottom.  Findings confirm that the bimodality of the grain size distribution generates a more efficient shearing arrangement, which can increase the mobility of granular flows in the same way recorded in debris avalanche deposits.</p>

Volcanic debris avalanches - from collapse to hazards

2020 ◽  
Author(s):  
Matteo Roverato ◽  
Anja Dufresne ◽  
Jon Procter
Keyword(s):  
Debris Avalanche ◽  
Future Research ◽  
Sector Collapse ◽  
Hazard Management ◽  
Volcano Collapse ◽  
Debris Avalanches ◽  
Destabilizing Factors ◽  
Volcanic Debris Avalanche ◽  
Volcanic Debris ◽  
Work Done

<p>This year marks the 40<sup>th</sup> anniversary of the 1980 Mt. St. Helens eruption and sector collapse. In acknowledgement to the vast research dedicated to understanding volcano collapse and debris avalanche dynamics, we have collated in a book the topic’s current state of the art. Within 12 chapters, this book contains reviews of and new insights from the work done over the past four decades, and provides outlooks and recommendations for future research. It is part of the Springer Book Series ‘Advances in Volcanology’ and the chapters contributed by a team of experts cover the following topics:</p><ol><li>Introduction </li> <li>A historical perspective on lateral collapse and debris avalanches</li> <li>Terminology and strategy to describe volcanic landslides and debris avalanches </li> <li>Distribution and geometric parameters of volcanic debris avalanche deposits </li> <li>Destabilizing factors that promote volcano flank collapse</li> <li>Volcanic debris avalanche transport kinematics and emplacement mechanisms</li> <li>Sedimentology of volcanic debris avalanche deposits</li> <li>Climatic and paleo-climatic implications </li> <li>Computer simulation of volcanic debris avalanches</li> <li>Volcanic debris avalanche deposits in the context of volcaniclastic ringplain successions</li> <li>Cyclicity in edifice destruction and regrowth </li> <li>Volcanic island lateral collapses and submarine volcanic debris avalanche deposits</li> </ol><p>Finally, the aim of the book is to reach the professional research community as well as students and a broader audience interested in hazard management in volcanic environments.</p>

scholarly journals Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

2006 ◽  
Vol 6 (5) ◽  
pp. 671-685 ◽  
Author(s):  
C. F. Waythomas ◽  
P. Watts ◽  
J. S. Walder
Keyword(s):  
Numerical Simulation ◽  
North Pacific Ocean ◽  
Debris Avalanche ◽  
Pyroclastic Flows ◽  
Tsunami Generation ◽  
Cook Inlet ◽  
Kenai Peninsula ◽  
Debris Avalanches ◽  
Short Period ◽  
Mass Flows

Abstract. Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12–14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.

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