Bedrock detection using 2D electrical resistivity imaging along the Peikang River, central Taiwan

Hsu, Han; Yanites, Brian J.; Chen, Chien Chih; Chen, Yue‐Gau

doi:10.1016/j.geomorph.2009.08.004

Cited by 57 publications

(39 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Yanites et al [2011] noted that incision rates in the Peikang River are proportional to (1) the frequency of bedrock exposure and (2) stream power. This field analysis occurred after the 1999 Chi Chi earthquake, in which an excess of sediment was introduced from hillslopes into the river, increasing the average thickness of alluvium, decreasing the frequency of bedrock exposure, and subsequently decreasing incision rates [Hsu et al, 2010;Yanites et al, 2010Yanites et al, , 2011.…”

Section: Occasional Bedrock Exposure In the Weak Zonementioning

confidence: 99%

A fault runs through it: Modeling the influence of rock strength and grain-size distribution in a fault-damaged landscape

Roy

Tucker

Koons

et al. 2016

J. Geophys. Res. Earth Surf.

View full text Add to dashboard Cite

We explore two ways in which the mechanical properties of rock potentially influence fluvial incision and sediment transport within a watershed: rock erodibility is inversely proportional to rock cohesion, and fracture spacing influences the initial grain sizes produced upon erosion. Fault‐weakened zones show these effects well because of the sharp strength gradients associated with localized shear abrasion. A natural example of fault erosion is used to motivate our calibration of a generalized landscape evolution model. Numerical experiments are used to study the sensitivity of river erosion and transport processes to variable degrees of rock weakening. In the experiments, rapid erosion and transport of fault gouge steers surface runoff, causing high‐order channels to become confined within the structure of weak zones when the relative degree of rock weakening exceeds 1 order of magnitude. Erosion of adjacent, intact bedrock produces relatively coarser grained gravels that accumulate in the low relief of the eroded weak zone. The thickness and residence time of sediments stored there depends on the relief of the valley, which in these models depends on the degree of rock weakening. The frequency with which the weak zone is armored by bed load increases with greater weakening, causing the bed load to control local channel slope. Conversely, small tributaries feeding into the weak zone are predominantly detachment limited. Our results indicate that mechanical heterogeneity can exert strong controls on rates and patterns of erosion and should be considered in future landscape evolution studies to better understand the role of heterogeneity in structuring landscapes.

show abstract

Section: Occasional Bedrock Exposure In the Weak Zonementioning

confidence: 99%

A fault runs through it: Modeling the influence of rock strength and grain-size distribution in a fault-damaged landscape

Roy

Tucker

Koons

et al. 2016

J. Geophys. Res. Earth Surf.

View full text Add to dashboard Cite

show abstract

“…In Taiwan, the damaging 1999 M w 7.6 Chi‐Chi earthquake and subsequent typhoons induced over 50 000 landslides across central Taiwan (Hung, ; Dadson et al ., ). These landslides had significant downstream impacts including increased fluvial suspended sediment discharge in the following few years after the event (Dadson et al ., ; Hovius et al ., ) and significant aggradation (3–12 m) of river beds due to excess bedload that persisted for at least a decade (Hsu et al ., ) and may persist for up to a century following the earthquake (Yanites et al ., ). The 2008 M w 7.9 Wenchuan earthquake caused extensive landslides that led to significant changes in sediment dynamics in the regional rivers (Wang et al ., ; Li et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Landslides control the spatial and temporal variation of channel width in southern Taiwan: Implications for landscape evolution and cascading hazards in steep, tectonically active landscapes

Yanites

Mitchell

Bregy

et al. 2018

Earth Surf Processes Landf

Self Cite

View full text Add to dashboard Cite

Intense precipitation or seismic events can generate clustered mass movement processes across a landscape. These rare events have significant impacts on the landscape, however, the rarity of such events leads to uncertainty in how they impact the entire geomorphic system over a range of timescales. Taiwan is steep, tectonically active, and prone to landslide and debris flows, especially when exposed to heavy rainfall events. Typhoon Morakot made landfall in Taiwan in August of 2009, causing widespread landslides in southern Taiwan. The south to north trend in valley relief in southern Taiwan leads to spatial variability in landslide susceptibility providing an opportunity to infer the long‐term impact of such landslide events on channel morphology. We use pre‐ and post‐typhoon imagery to quantify the propagating impact of this event on channel width as the debris is routed through the landscape. The results show the importance of cascading hazards from landslides on landscape evolution based on patterns of channel width (both pre‐ and post‐typhoon) and hillslope gradients in 20 basins along strike in southern Taiwan. Prior to Typhoon Morakot, the river channels in the central part of the study area were about 3–10 times wider than the channels in the south. Following the typhoon, aggradation and widening was also a maximum in these central to northern basins where hillslope gradients and channel steepness is high, accentuating the pre‐typhoon pattern. The results further show that the narrowest channels are located where channel steepness is the lowest, an observation inconsistent with a detachment‐limited model for river evolution. We infer this pattern is indicative of a strong role of sediment supply, and associated landslide events, on long‐term channel evolution. These findings have implications across a range of spatial and temporal scales including understanding the cascade of hazards in steep landscapes and geomorphic interpretation of channel morphology. Copyright © 2018 John Wiley & Sons, Ltd.

show abstract

“…() and Hsu et al . (). In this section, I will develop a procedure that finds layer boundaries in MLMs using the continuous wavelet transform (CWT).…”

Section: Few‐layer Model Inversion Modelsmentioning

confidence: 97%

“…Finding layer boundaries in inversion models to compensate for the blurry definition of formation boundaries in multilayer models (MLMs) has been a research effort in several instances, for example, reported by Chambers et al (2010) and Hsu et al (2010). In this section, I will develop a procedure that finds layer boundaries in MLMs using the continuous wavelet transform (CWT).…”

Section: Finding Layer Boundaries In Multi-layer Modelsmentioning

confidence: 99%

Interpretation attributes derived from airborne electromagnetic inversion models using the continuous wavelet transform

Christensen

2018

Near Surface Geophysics

View full text Add to dashboard Cite

Planning, contracting, data acquisition and processing plus the inverter's quality assessment and inversion of a regional airborne electromagnetic survey may take some months, while the interpretation of the results is a considerably more complex and comprehensive process. Most often an interpretation necessitates additional data that are time consuming to collect and complicated to integrate into an overall model, for example borehole logs, borehole core samples, water chemistry, surface vegetation, satellite imagery plus all existing geological background knowledge. Interpretation basically has to do with identifying categories and finding boundaries between them so that depths, thicknesses and a whole range of other model attributes can be estimated, qualitatively and/or quantitatively. I present two methods using the continuous wavelet transform of finding attributes intended to assist the interpreter: one finds layer boundaries in the smooth multi‐layer models that are most often used in the inversion of large airborne electromagnetic data sets, and the other finds the natural categories of the model parameter. Naturally, being based on the subsurface conductivity distribution, the boundaries and categories suggested are useful only to the extent that they coincide with geological/hydrogeological boundaries and categories – which is for the interpreter to decide.

show abstract

Bedrock detection using 2D electrical resistivity imaging along the Peikang River, central Taiwan

Cited by 57 publications

References 19 publications

A fault runs through it: Modeling the influence of rock strength and grain-size distribution in a fault-damaged landscape

A fault runs through it: Modeling the influence of rock strength and grain-size distribution in a fault-damaged landscape

Landslides control the spatial and temporal variation of channel width in southern Taiwan: Implications for landscape evolution and cascading hazards in steep, tectonically active landscapes

Interpretation attributes derived from airborne electromagnetic inversion models using the continuous wavelet transform

Contact Info

Product

Resources

About