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Topic 3 - Debris-flow Deposits and Fan Morphology

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Topic 3 - Debris-flow Deposits and Fan Morphology
Affected by the active plate motion, the upper Minjiang River develops more than 21 debris flow valleys. After the Wenchuan earthquake on May 12, 2008, the geohazards occur more frequently and seriously because of the increased debris source, and 9 debris flows blocked the mainstream. Based on the characteristics of debris-flow dams, model tests have been accomplished. Given the junction angle of 90°, influence of debris flow on channel evolution is discussed for different flow density, and discharge ratio
Topic 3 - Debris-flow Deposits and Fan Morphology
With the rapid development of the Chinese economy, many important building projects are planned on debris fans. Because of their location, these new constructions will be threatened by debris flows. Thus, it is important to study debris flow deposition in different conditions. Twenty debris fans under different experimental conditions are considered in order to examine the geometric similarity of debris flow deposition. The experimental results show that the cross-section, profile, and plane configuration
Topic 3 - Debris-flow Deposits and Fan Morphology
In 1999, the Mars Global Surveyor acquired images of young gully features on the walls of impact craters. From these and subsequent images, numerous theoretical and physical models have been developed based primarily on three competing theories about the origin of the gullies: 1) scour and deposition by dry granular flows, 2) debris flow driven gully incision due to the sudden release of gases or fluid from the subsurface, or 3) fluid incision via debris flows due to the release of surface volatiles or the
Topic 3 - Debris-flow Deposits and Fan Morphology
Typically runout prediction methods - either based on empirical or on dynamical approaches - are applied to delineate possible debris-flow inundation zones on the fan for hazard mapping purposes. However, several case studies indicate that empirical relations may be valid only for situations which are similar to those represented by the data used for their development, and that a more accurate description of the debrisflow depositional process requires dynamical parameters which are often not easily constra
Topic 3 - Debris-flow Deposits and Fan Morphology
In this paper we present the rationale for a new approach to the modelling of debris-flow fans. Understanding debris-flow fan evolution is important for two reasons: fans are potential archives of past environmental conditions of mountain belts, and they are commonly inhabited despite the threat of debris flow occurrence. There are currently no models available that adequately represent debris flows as agents of geomorphic landscape change over the time scales (103 to 106 y) necessary to construct fans, whi
Topic 3 - Debris-flow Deposits and Fan Morphology
Studies on debris-flow fan configurations are fundamental to map hazard zone of debris flow disasters. This study aims to identify the morphological similarity of debris-flow fans based on a series of laboratory experiments and field investigations. The maximum length Lc, width Bm and thickness Zo of debris-flow fans are adopted as the characteristic parameters for analyzing the morphological similarity. The analysis demonstrates that the non-dimensional longitudinal and transverse profiles of debris-flow f
Topic 3 - Debris-flow Deposits and Fan Morphology
The Liziao Gully and Huajiaopo Gully are 2 tributaries of Jiangjia Gully in its middle reaches, a well-known gully for its debris flows of high frequency. The two gullies are extremely similar in features of their drainage basins, including high frequency of debris flows and rapid formulation of debris flow fans. During field studies, process of movement and accumulation of debris flow fan are observed, and sampling and analysis of debris flows with different features are conducted. Terrain of debris flow
Topic 3 - Debris-flow Deposits and Fan Morphology
Debris flows, widespread in mountainous areas of China, transport large amounts of sediment in small intervals of time. To investigate the effects of debris flows on channel morphology, we chose 10 cross-sections to monitor periodic series of multiple debris flows triggered by summer rainstorms at Jiangjia ravine, Yunnan province, southwestern China. The 10 sections were distributed in the upper, middle, and lower sections of the trunk drainage to record erosion and deposition. Based on the observation da
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