Landscape and hazard evolution during the Montserrat volcanic crisis 1995–2010: an integrated simulation with r.avaflow

2021 ◽  
Author(s):  
Martin Mergili ◽  
Shiva P. Pudasaini
Keyword(s):  
Lava Dome ◽  
Flow Simulation ◽  
Active Phase ◽  
Predictive Modelling ◽  
Pyroclastic Flows ◽  
Integrated Simulation ◽  
Ash Fall ◽  
Multi Stage ◽  
Dome Growth ◽  
The Impact

<p>An active phase of Soufrière Hills Volcano (Montserrat, Lesser Antilles) has started in 1995 and had its most intense period between 1995 and 2010, when phases of lava dome growth were interrupted by dome collapses triggering ash clouds and different types of pyroclastic flows. These flows were released in various directions, so that two thirds of the island were left in an inhabitable state. The material deposited was later remobilized through lahar flows, burying the centre of the former capital town of Plymouth. In the present work, we attempt to back-calculate the sequences of dome growth – pyroclastic flows, and the subsequent lahar flows, in an integrated way, using the mass flow simulation tool r.avaflow. Thereby, we build on the reconstruction of the pre-event topography as well as on various reference data obtained from the large amount of available literature – mainly, the peak elevation and volumes of the lava domes, the impact areas of the flow processes, and ash fall characteristics. Most observations are successfully reproduced with physically plausible, though calibrated, parameter sets and temporal scaling of lava dome growth. Due to the complexity and multi-stage nature of the volcanic crisis, a number of simplifications had to be introduced, such as considering only the twelve largest sequences of dome growth and pyroclastic flows, and evaluating some of the results on the basis of aggregated impact areas for more than one event. Consequently, the results reflect a strong conceptual component, but can - at least in part - be considered useful for predictive modelling of similar events. Another scope of the simulation results, however, is its educational use. Appropriately presented, they greatly facilitate the generation of a better understanding for complex chains of volcanic processes and their consequences to learners at various levels in different educational contexts, from school and university all the way to targeted awareness-building campaigns.</p>

Pemodelan Aliran Awanpanas (Aliran Piroklastik) Sebagai Data Pendukung Peta Kawasan Rawan Bencana Gunungapi (Studi Kasus Gunungapi Sinabung Sumatra Utara) Pyroclastic Flows Modeling As A Supporting Data For Volcanic Hazard Map (Case Study Sinabung Volcano-North Sumatra)

2017 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Agoes Loeqman ◽  
Nana Sulaksana ◽  
A. Helman Hamdani ◽  
Wening Sulistri
Keyword(s):  
Pyroclastic Flow ◽  
Simulation Modeling ◽  
Lava Dome ◽  
Volcanic Hazard ◽  
Flow Simulation ◽  
Pyroclastic Flows ◽  
Geographical Information ◽  
Hazard Map ◽  
Volcano Eruption ◽  
Volcanic Hazard Map

ABSTRAKIndonesia mempunyai 127 gunungapi aktif dan berdasarkan sejarah erupsi 67 di antaranya merupakan gunungapi berbahaya. Erupsi gunungapi memiliki risiko merusak dan mematikan tidak hanya bagi masyarakat yang bermukimdi sekitarnya tapi juga menyebabkan bencana bagi masyarakat luas. Salah satu bahaya primer erupsi gunungapi adalah aliran awanpanas, produk erupsi gunungapi yang sampai saat ini paling banyak menyebabkan jatuhnya korban jiwa, untuk itu diperlukan suatu simulasi/pemodelan untuk mengetahui pola aliran awanpanas guna mendukung penentuan Kawasan Rawan Bencana (KRB) erupsi gunungapi.Simulasi/pemodelan aliran awanpanas ini dibuat berdasarkan data Model Elevasi Digital (DEM) dan memanfaatkan aplikasi Sistem Informasi Geografis (GIS), dengan output berupa representasi dinamis dari kecepatan aliran awanpanas, ketebalan deposit, dan daerah terdampak, dengan studi kasusGunungapi Sinabung Sumatra Utara. Setelah erupsi terakhir 1200 tahun lalu peningkatan aktivitas Gunungapi sinabung ditandai dengan terjadinya letusan freatik pada periode Agustus-September 2010. Setelah 3 tahun beristirahat, aktivitas erupsi kembali terjadi sejak September 2013 hingga saat ini. Aktivitas erupsi berupa pertumbuhan kubah lava dan luncuran awanpanas telah mengakibatkan jatuhnya korban jiwa serta memaksa penduduk mengungsi menjauhi daerah bahaya.Simulasi/pemodelan aliran awanpanas Gunungapi Sinabung karena runtuhnya kubah lava dibuat ke berbagai arah dengan skenario volume kubah lava ; 1, 2 dan 3 juta m3. Hasil overlay antara daerah landaaan awanpanas dengan skenario 3 juta m3 pada Peta KRB menunjukan jangkauan aliran awanpanas pada sektor tenggara, barat dan timurlaut telah sedikit melewati batas KRB III (kawasan sangat berpotensi terlanda awan panas, aliran lava, guguran lava dangas beracun).Kata kunci : awanpanas, Simulasi/model, titan2d, KRBABSTRACTIndonesia has 127 active volcanoes and based on historical eruption, 67 of them are dangerous. Volcano eruption having destructive risk and deadly, not only for the people who lived around, but also caused disaster for large society. One of the primary danger of volcano eruption is the pyroclastic flow, volcano eruption products that until recently was the most caused the loss of life, therefore necessary creating a simulation/modeling to know pyroclastic flow pattern to support of a determination the Volcanic hazard map. Pyroclastic flow Simulation/modeling is made based on the Digital Elevation Model (DEM) data and using Geographical Information System (GIS) application, with output of representation dynamic from the pyroclastic flow velocity, the thickness of deposit, and affected areas, with case Sinabung Volcano in North Sumatra.Since lates eruption about 1.200 years ago, Increased activity Sinabung volcano started by phreatic eruptions during August – September 2010. After three years of rest, eruption activity occurs again on September 2013 until today, with lava dome growth and pyroclastic flow acitvity have caused casualties and forcing residents were being evacuated away from the danger area.The pyroclastic flow simulation/modeling due the lava dome collapse is made into various directions with scenario of lava dome volume ; 1, 2 and 3 million m3. The results of overlay between areas affected by pyroclastic flow model with scenario 3 million m3 and volcanic hazard map showed the range of pyroclastic flow to the southeast, west and northeast sector reached the limit of zone III at volcanic hazard map (Very potentially affected by pyroclastic flow, lava flow, lava avalanche, and toxic volcanic gas ).Keywords : pyroclastic, simulation/modeling Titan2D, volcanic hazard map

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

Assessment of Unsteady Flows in Turbines

1992 ◽  
Vol 114 (1) ◽  
pp. 79-90 ◽  
Author(s):  
O. P. Sharma ◽  
G. F. Pickett ◽  
R. H. Ni
Keyword(s):  
Unsteady Flow ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Experimental Investigations ◽  
Flow Parameters ◽  
Research Activities ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
The Impact

The impacts of unsteady flow research activities on flow simulation methods used in the turbine design process are assessed. Results from experimental investigations that identify the impact of periodic unsteadiness on the time-averaged flows in turbines and results from numerical simulations obtained by using three-dimensional unsteady Computational Fluid Dynamics (CFD) codes indicate that some of the unsteady flow features can be fairly accurately predicted. Flow parameters that can be modeled with existing steady CFD codes are distinguished from those that require unsteady codes.

Dynamics of the Gear Train Set in Wind Turbine

2011 ◽  
Vol 697-698 ◽  
pp. 701-705
Author(s):  
D.D. Ji ◽  
Y.M. Song ◽  
J. Zhang
Keyword(s):  
Wind Turbine ◽  
Dynamic Model ◽  
Harmonic Balance Method ◽  
Planetary Gear ◽  
Gear Train ◽  
Dynamic Responses ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Cartesian Coordinate ◽  
The Impact

A lumped-parameter dynamic model for gear train set in wind turbine is proposed to investigate the dynamics of the speed-increasing gear box. The proposed model is developed in a universal Cartesian coordinate, which includes transversal and torsional deflections of each component, time-varying mesh stiffness, gear profile errors and external excitations. By solving the dynamic model, a modal analysis is performed. The results indicate that the modal properties of the multi-stage gear train in wind turbine are similar to those of a single-stage planetary gear set. A harmonic balance method (HBM) is used to obtain the dynamic responses of the gearing system. The responses give insight into the impact of excitations on the vibrations.

scholarly journals Using video games for volcanic hazard education and communication: an assessment of the method and preliminary results

2016 ◽  
Vol 16 (7) ◽  
pp. 1673-1689 ◽  
Author(s):  
Lara Mani ◽  
Paul D. Cole ◽  
Iain Stewart
Keyword(s):  
Video Games ◽  
Video Game ◽  
Volcanic Hazard ◽  
Pyroclastic Flows ◽  
Concept Design ◽  
Preliminary Results ◽  
Ash Fall ◽  
Post Test ◽  
Hazard Education ◽  
Sound Foundation

Abstract. This paper presents the findings from a study aimed at understanding whether video games (or serious games) can be effective in enhancing volcanic hazard education and communication. Using the eastern Caribbean island of St. Vincent, we have developed a video game – St. Vincent's Volcano – for use in existing volcano education and outreach sessions. Its twin aims are to improve residents' knowledge of potential future eruptive hazards (ash fall, pyroclastic flows and lahars) and to integrate traditional methods of education in a more interactive manner. Here, we discuss the process of game development including concept design through to the final implementation on St. Vincent. Preliminary results obtained from the final implementation (through pre- and post-test knowledge quizzes) for both student and adult participants provide indications that a video game of this style may be effective in improving a learner's knowledge. Both groups of participants demonstrated a post-test increase in their knowledge quiz score of 9.3 % for adults and 8.3 % for students and, when plotted as learning gains (Hake, 1998), show similar overall improvements (0.11 for adults and 0.09 for students). These preliminary findings may provide a sound foundation for the increased integration of emerging technologies within traditional education sessions. This paper also shares some of the challenges and lessons learnt throughout the development and testing processes and provides recommendations for researchers looking to pursue a similar study.

scholarly journals Post-Closure Safety Analysis of Nuclear Waste Disposal in Deep Vertical Boreholes

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6356
Author(s):  
Stefan Finsterle ◽  
Richard A. Muller ◽  
John Grimsich ◽  
Ethan A. Bates ◽  
John Midgley
Keyword(s):  
Land Surface ◽  
Spent Nuclear Fuel ◽  
Hydrological Cycle ◽  
Decay Chain ◽  
Geothermal Gradient ◽  
Great Depth ◽  
Salinity Stratification ◽  
Integrated Simulation ◽  
Safety Features ◽  
The Impact

Isolation of spent nuclear fuel assemblies in deep vertical boreholes is analyzed. The main safety features of the borehole concept are related to the repository’s great depth, implying (a) long migration distances and correspondingly long travel times, allowing radionuclides to decay, (b) separation of the repository from the dynamic hydrological cycle near the land surface, (c) stable geological and hydrogeological conditions, and (d) a geochemically reducing environment. An integrated simulation model of the engineered and natural barrier systems has been developed to examine multiple scenarios of the release of radionuclides from the waste canisters, the transport through a fractured porous host rock, and the extraction of potentially contaminated drinking water from an aquifer. These generic simulations include thermal effects from both the natural geothermal gradient and the heat-generating waste, the influence of topography on regional groundwater flow, moderated by salinity stratification at depth, and the role of borehole sealing. The impact of these processes on the transport of select radionuclides is studied, which include long-lived, soluble, sorbing or highly mobile isotopes along with a decay chain of safety-relevant actinide metals. The generic analyses suggest that a deep vertical borehole repository has the potential to be a safe option for the disposal of certain waste streams, with the depth itself and the stable hydrogeological environment encountered in the emplacement zone providing inherent long-term isolation, which allows for reduced reliance on a complex engineered barrier system.

scholarly journals Insights into the Cellular and Molecular Mechanisms That Govern the Fracture-Healing Process: A Narrative Review

2021 ◽  
Vol 10 (16) ◽  
pp. 3554
Author(s):  
Dionysios J. Papachristou ◽  
Stavros Georgopoulos ◽  
Peter V. Giannoudis ◽  
Elias Panagiotopoulos
Keyword(s):  
Fracture Healing ◽  
Bone Repair ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Healing Process ◽  
Bone Architecture ◽  
Multi Stage ◽  
Stage Process ◽  
And Function ◽  
The Impact

Fracture-healing is a complex multi-stage process that usually progresses flawlessly, resulting in restoration of bone architecture and function. Regrettably, however, a considerable number of fractures fail to heal, resulting in delayed unions or non-unions. This may significantly impact several aspects of a patient’s life. Not surprisingly, in the past few years, a substantial amount of research and number of clinical studies have been designed, aiming at shedding light into the cellular and molecular mechanisms that regulate fracture-healing. Herein, we present the current knowledge on the pathobiology of the fracture-healing process. In addition, the role of skeletal cells and the impact of marrow adipose tissue on bone repair is discussed. Unveiling the pathogenetic mechanisms that govern the fracture-healing process may lead to the development of novel, smarter, and more effective therapeutic strategies for the treatment of fractures, especially of those with large bone defects.

Sign in / Sign up

Export Citation Format

Share Document