Long-term lahar reconstruction in Jamapa Gorge, Pico de Orizaba (Mexico) based on botanical evidence and numerical modelling

Landslides ◽  
2021 ◽  
Author(s):  
José Ernesto Figueroa-García ◽  
Osvaldo Franco-Ramos ◽  
José María Bodoque ◽  
Juan Antonio Ballesteros-Cánovas ◽  
Lorenzo Vázquez-Selem
Keyword(s):  
Numerical Modelling

scholarly journals Autogenic versus allogenic controls on the evolution of a coupled fluvial megafan/mountainous catchment system: numerical modelling and comparison with the Lannemezan megafan system (Northern Pyrenees, France)

2016 ◽  
Author(s):  
Margaux Mouchené ◽  
Peter van der Beek ◽  
Sébastien Carretier ◽  
Frédéric Mouthereau
Keyword(s):  
Numerical Modelling ◽  
Temporal Variations ◽  
Tectonic Activity ◽  
Mountain Range ◽  
Stream Network ◽  
Mountainous Catchment ◽  
Isostatic Rebound ◽  
Base Level ◽  
Alluvial Terraces

Abstract. Alluvial megafans are sensitive recorders of landscape evolution, controlled by autogenic processes and allogenic forcing and influenced by the coupled dynamics of the fan with its mountainous catchment. The Lannemezan megafan in the northern Pyrenean foreland was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised, leaving a flight of alluvial terraces along the stream network. We explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan using numerical modelling and compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river at time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision at a shorter time-scale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound appear unimportant.

scholarly journals Two decades of numerical modelling to understand long term fluvial archives: Advances and future perspectives

2017 ◽  
Vol 166 ◽  
pp. 177-187 ◽  
Author(s):  
A. Veldkamp ◽  
J.E.M. Baartman ◽  
T.J. Coulthard ◽  
D. Maddy ◽  
J.M. Schoorl ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Future Perspectives ◽  
Fluvial Archives

THREE-DIMENSIONAL NUMERICAL MODELLING OF RESERVOIR FLUSHING TO OBTAIN LONG-TERM SEDIMENT EQUILIBRIUM

2019 ◽  
Author(s):  
LEON SAAM ◽  
KILIAN MOURIS ◽  
SILKE WIEPRECHT ◽  
STEFAN HAUN
Keyword(s):  
Numerical Modelling ◽  
Three Dimensional

Long-term investigation of a deep-seated creeping landslide in crystalline rock. Part II. Mitigation measures and numerical modelling of deep drainage at Campo Vallemaggia

2007 ◽  
Vol 44 (10) ◽  
pp. 1181-1199 ◽  
Author(s):  
E. Eberhardt ◽  
L. Bonzanigo ◽  
S. Loew
Keyword(s):  
Numerical Modelling ◽  
Distinct Element ◽  
Companion Paper ◽  
Crystalline Rock ◽  
Swiss Alps ◽  
Mitigation Measures ◽  
Extensive Investigation ◽  
Deep Drainage ◽  
Measured Response

For more than 200 years, the villages of Campo Vallemaggia and Cimalmotto have been slowly moving on top of a deep-seated landslide in the southern Swiss Alps. Numerous mitigation measures have been carried out during this time to stabilize the landslide but with limited to no success. Those attempts largely focussed on minimizing erosion at the toe of the landslide. More recently, the need to stabilize the slope began to intensify, as with each passing year the two villages were being pushed closer to the edge of a 100 m high erosion front at the foot of the landslide. This led to an extensive investigation and monitoring campaign to better understand the factors controlling the landslide movements, which as reported in Part I (see companion paper, this issue), pointed to high artesian pore pressures as being the primary destabilizing mechanism. Here in Part II, the arguments supporting the need for a deep drainage solution are reported, as is the history, implementation, and measured response of the Campo Vallemaggia landslide to the various mitigative measures taken. Numerical modelling results are also presented, based on hydromechanically coupled distinct-element models, to help demonstrate why deep drainage succeeded where other mitigation measures failed.

scholarly journals NATM TUNNELS – CONSIDERATION OF THE PARTLY DAMAGED PRIMARY LINING IMPACT FOR THE SECONDARY LINING EVALUATION

2020 ◽  
Vol 60 (2) ◽  
pp. 145-150
Author(s):  
Vlastislav Trunda ◽  
Matouš Hilar
Keyword(s):  
Numerical Modelling ◽  
Sprayed Concrete ◽  
Cast Concrete ◽  
Secondary Lining ◽  
Static Evaluation

Tunnels excavated by the New Austrian Tunnelling Method (NATM) are traditionally supported by a double-shell lining. The primary lining is generated from reinforced sprayed concrete with rockbolts, the secondary lining is generated from in-situ cast concrete and it is protected by a waterproof membrane. The static evaluation of the long term behaviour generally assumes full degradation of the primary lining (the primary lining impact is not considered). Some investigations of tunnels constructed in past indicated that the primary lining degradation is slower than expected. This paper discusses possibilities of partly damaged primary lining consideration in static calculations of the secondary lining. Various options were verified by numerical modelling, and its results were compared and discussed.

Underplating altered oceanic crust: Insights from numerical modelling

2021 ◽  
Author(s):  
Zoe Braden ◽  
Jonas B. Ruh ◽  
Whitney M. Behr
Keyword(s):  
Numerical Modelling ◽  
Oceanic Crust ◽  
Fluid Pressure ◽  
Geothermal Gradient ◽  
Pore Fluid ◽  
Surface Erosion ◽  
Accretionary Wedge ◽  
Pore Fluid Pressure ◽  
Mafic Rocks

<p>Observations of several active shallow subduction megathrusts suggest that they are localized as décollements within sedimentary sequences or at the contact between sedimentary layers and the underlying mafic oceanic crust.  Exhumed accretionary complexes from a range of subduction depths, however, preserve underplated mafic slivers, which indicate that megathrust faults can occasionally develop within the mafic oceanic crustal column. The incorporation of mafic rocks into the subduction interface shear zone has the potential to influence both long-term subduction dynamics and short-term seismic and transient slip behaviour, but the processes and conditions that favour localisation of the megathrust into deeper oceanic crustal levels are poorly understood.</p><p>In this work, we use visco-elasto-plastic numerical modelling to explore the long-term (million year) factors influencing the incorporation of mafic volcanic rocks into the subduction interface and accretionary wedge through underplating. We focus on the potential importance of oceanic seafloor alteration in facilitating oceanic crustal weakening, which is implemented through a temperature-dependent pore-fluid pressure ratio (lambda = 0.90-0.99 between 160 and 300oC). We then examine the underplating response to changes in sediment thickness, geothermal gradient, sediment fluid pressure, and surface erosion rates. Our results indicate that a thinner incoming sediment package and a lower geothermal gradient cause oceanic crustal underplating to initiate deeper beneath the backstop (overriding plate) compared to thicker incoming sediment and a higher geothermal gradient. Relative pore fluid pressure differences between sediments and altered oceanic crust control the amount of altered oceanic crust that is underplated, as well as the location of underplating beneath the backstop or accretionary wedge. When sediments on top of the altered oceanic crust have the same fluid pressure as the altered oceanic crust, no oceanic crustal underplating occurs. Modelling results are also compared to exhumed subduction complexes to examine the amount and distribution of underplated mafic rocks.</p>

NUMERICAL MODELLING OF LONG-TERM MORPHOLOGY IN THE SURF ZONE OF THE BELGIAN COAST

2014 ◽  
Vol 1 (34) ◽  
pp. 42
Author(s):  
Li Wang ◽  
Nicolas Zimmermann ◽  
Koen Trouw ◽  
Bart De Maerschalck ◽  
Joris Vanlede
Keyword(s):  
Numerical Modelling ◽  
Surf Zone ◽  
Belgian Coast

scholarly journals Mid-Holocene thinning of David Glacier, Antarctica: chronology and controls

2021 ◽  
Vol 15 (12) ◽  
pp. 5447-5471
Author(s):  
Jamey Stutz ◽  
Andrew Mackintosh ◽  
Kevin Norton ◽  
Ross Whitmore ◽  
Carlo Baroni ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Catchment Scale ◽  
Peak Period ◽  
Outlet Glacier ◽  
Geological Past ◽  
Victoria Land ◽  
Exposure Ages

Abstract. Quantitative satellite observations only provide an assessment of ice sheet mass loss over the last four decades. To assess long-term drivers of ice sheet change, geological records are needed. Here we present the first millennial-scale reconstruction of David Glacier, the largest East Antarctic outlet glacier in Victoria Land. To reconstruct changes in ice thickness, we use surface exposure ages of glacial erratics deposited on nunataks adjacent to fast-flowing sections of David Glacier. We then use numerical modelling experiments to determine the drivers of glacial thinning. Thinning profiles derived from 45 10Be and 3He surface exposure ages show David Glacier experienced rapid thinning of up to 2 m/yr during the mid-Holocene (∼ 6.5 ka). Thinning slowed at 6 ka, suggesting the initial formation of the Drygalski Ice Tongue at this time. Our work, along with ice thinning records from adjacent glaciers, shows simultaneous glacier thinning in this sector of the Transantarctic Mountains occurred 4–7 kyr after the peak period of ice thinning indicated in a suite of published ice sheet models. The timing and rapidity of the reconstructed thinning at David Glacier is similar to reconstructions in the Amundsen and Weddell embayments. To identify the drivers of glacier thinning along the David Glacier, we use a glacier flowline model designed for calving glaciers and compare modelled results against our geological data. We show that glacier thinning and marine-based grounding-line retreat are controlled by either enhanced sub-ice-shelf melting, reduced lateral buttressing or a combination of the two, leading to marine ice sheet instability. Such rapid glacier thinning events during the mid-Holocene are not fully captured in continental- or catchment-scale numerical modelling reconstructions. Together, our chronology and modelling identify and constrain the drivers of a ∼ 2000-year period of dynamic glacier thinning in the recent geological past.

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