Triggering mechanisms and depositional rates of postglacial slope-movement processes in the Yosemite Valley, California

Wieczorek, Gerald F.; Jäger, Sebastian

doi:10.1016/0169-555x(95)00112-i

Cited by 142 publications

(102 citation statements)

References 11 publications

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“…Many of the larger debris slides and flows have also initiated in saprolite or colluvium within the zone of weathered rock above the level of Tioga glaciation. At a lower elevations, most of the valley has probably been free of glacial ice since about 15 000 yBP (Wieczorek and Jäeger, 1996), and only quite small rock falls and slides have occurred within the jointed granitic rocks below the level of Tioga glaciation.…”

Section: Landslides In Yosemitementioning

confidence: 99%

Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

Bertolo

Wieczorek

2005

Nat. Hazards Earth Syst. Sci.

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Abstract. This study compares documented debris flow runout distances with numerical simulations in the Yosemite Valley of California, USA, where about 15% of historical events of slope instability can be classified as debris flows and debris slides (Wieczorek and Snyder, 2004).To model debris flows in the Yosemite Valley, we selected six streams with evidence of historical debris flows; three of the debris flow deposits have single channels, and the other three split their pattern in the fan area into two or more channels. From field observations all of the debris flows involved coarse material, with only very small clay content.We applied the one dimensional DAN (Dynamic ANalysis) model (Hungr, 1995) and the two-dimensional FLO-2D model (O'Brien et al., 1993) to predict and compare the runout distance and the velocity of the debris flows observed in the study area. As a first step, we calibrated the parameters for the two softwares through the back analysis of three debris-flows channels using a trial-and-error procedure starting with values suggested in the literature. In the second step we applied the selected values to the other channels, in order to evaluate their predictive capabilities.After parameter calibration using three debris flows we obtained results similar to field observations We also obtained a good agreement between the two models for velocities. Both models are strongly influenced by topography: we used the 30 m cell size DTM available for the study area, that is probably not accurate enough for a highly detailed analysis, but it can be sufficient for a first screening.

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Section: Landslides In Yosemitementioning

confidence: 99%

Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

Bertolo

Wieczorek

2005

Nat. Hazards Earth Syst. Sci.

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“…Wieczorek and Jäger (1996), for example, described the historical reports that they used for the inventory of slope movements in the Yosemite Valley of California as frequently fragmentary or inconsistent, which consequently resulted in the underestimation of the actual number of events. In this study, the problem was further complicated by the complexity of Italian history.…”

Section: The Importance Of the Combined Historical-geological Approacmentioning

confidence: 99%

Combining historical and geological data for the assessment of the landslide hazard: a case study from Campania, Italy

Calcaterra

Parise

Palma

2003

Nat. Hazards Earth Syst. Sci.

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Abstract. Past slope instabilities at Quindici (one of the five towns of Campania that was hit by catastrophic landslides on 5 May 1998) and in the Lauro Valley are investigated to improve the understanding of the landslide history in the area, as a mandatory step for the evaluation of the landslide hazard. The research was performed by combining information on past slope instabilities from both historical and geological data. From numerous historical sources an archive consisting of 45 landsliding and flooding events for the period 1632-1998 was compiled. Landslide activity was also investigated by means of interpretation of multi-year sets of aerial photos, production of Landslide Activity Maps, and excavation of trenches on the alluvial fans at the mountain foothills. Detailed stratigraphic analysis of the sections exposed in the trenches identified landslide events as the main geomorphic process responsible for building up the fans in the study area. Integration of historical and geological approaches provides significant insight into past and recent instability at Quindici. This is particularly valuable in view of the limitations of individual sources of information. Application of such an approach offers potential for improved hazard assessment and risk mitigation.

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“…the tensile strength of the large-scale rock material or incipient joint (expressed in force units) F LC Measured force (kN) using load cell F LCA and F LCB Measured force (kN) using load cell A and load cell B, respectively F PR Measured force (kN) using proving ring ETF (t) The total expansive tensile force (kN) perpendicular to the splitting plane from expansive grout tensile strength (following the definition of ISRM [17]), in response to temperature and insolation [5], precipitation [39], weathering [4,[11][12][13], seismic loading [7] and mechanical breakage. Figure 1a shows a piece of finegrained sandstone core containing many incipient rock joint traces that were not fully developed, due to the presence of rock bridges having considerable tensile strength.…”

Section: List Of Symbols F D(t)mentioning

confidence: 99%

Tensile strength of large-scale incipient rock joints: a laboratory investigation

et al. 2017

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In this paper, a testing methodology was developed in the laboratory to measure the tensile strength of large-scale incipient rock joints. In the test, an expansive grout was used to develop the tensile force. Each test comprises two phases: Phase i test and Phase ii test. The Phase i test identified sample failure time, while the Phase ii test measured the corresponding tensile force arising from the expansive grout. Ostensibly homogeneous rock samples without incipient joints were firstly tested to establish the methodology. Tensile strength of block samples containing incipient rock joints was then measured using the established testing scheme. The test results have been compared with those obtained from conventional Brazilian and uniaxial tension tests as suggested by ISRM. The proposed approach is capable of giving a measure of tensile strength of large-scale incipient rock joints, although somewhat smaller strength than that from the standard approaches was occasionally measured in the preliminary tests on ostensibly homogeneous samples. Effects of stress concentration, sample scale, loading rate and expansive tensile force on the testing results were discussed. Furthermore, this simple and practical testing scheme is proposed for the measurement of the in situ tensile strength of rock and incipient discontinuities in the field, which if successful will provide a more scientific guidance on the rock mass classification and engineering design.

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Triggering mechanisms and depositional rates of postglacial slope-movement processes in the Yosemite Valley, California

Cited by 142 publications

References 11 publications

Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

Combining historical and geological data for the assessment of the landslide hazard: a case study from Campania, Italy

Tensile strength of large-scale incipient rock joints: a laboratory investigation

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