Catastrophic Landslides of Pyroclastics Induced by the 2011 off the Pacific Coast of Tohoku Earthquake

Chigira, Masahiro; Nakasuji, Akito; Fujiwara, Seiji; Sakagami, Masayuki

doi:10.1007/978-3-642-32238-9_15

Cited by 10 publications

(11 citation statements)

References 10 publications

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“…We also performed undrained shear tests on fully saturated air-dried or oven-dried samples of S1 to examine the possible effect of drying process on its undrained shear behavior. As pointed out by Chigira et al (2012), the dominant clay mineral in the palaeosol of the studied landslides is halloysite, which is normally formed by hydrothermal alteration of volcanic rocks (Kerr, 1952); while air or oven drying would result in the dehydration of interlayer water of halloysite (Wesley, 1973(Wesley, , 1977Okada and Ossaka, 1983). Nevertheless, detailed examination on the possible effects of drying process on palaeosol properties is beyond the focus of this study; here we only present the results of tests on those samples with natural moisture contents.…”

Section: Setup Of Shear Testmentioning

confidence: 89%

Some fluidized landslides triggered by the 2011 Tohoku Earthquake (Mw 9.0), Japan

Wang¹,

Suemine²,

Zhang³

et al. 2014

Geomorphology

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The 2011 Tohoku Earthquake off the Pacific coast of Japan generated a large tsunami and many landslides, resulting in a great number of casualties. Although almost all casualties resulted from the tsunami, some long-travel, fluidized small-scale landslides also killed 13 people. After the earthquake, we surveyed seven of these catastrophic landslides triggered by the earthquake. We found that most of them have nearly identical geological features, with slopes consisting of pyroclastic deposits formed at different times, and with a palaeosol layer that outcropped in most cases after the landslide. Above the palaeosol there are layers of pumice and scoria. The palaeosol had a natural moisture content of ~160%, and the pumice and scoria a moisture content of ~145%. From field observations we concluded that the sliding surface originated in the very upper part of palaeosol, and liquefaction occurred in both layers, resulting in the fluidization of displaced landslides. To examine the trigger and movement mechanism of these landslides, we monitored the ground motion of one landslide area during the many aftershocks, and compared the results with records obtained by a national seismic station nearby. We inferred that strong seismic motion occurred in the landslide area during the main shock. We sampled the palaeosol and pyroclastic deposits, and performed undrained static/cyclic shear tests on the materials both in a saturated state and at natural moisture content. The results indicate that high pore-water pressure generated, resulting in decreased shear strength even in samples with the natural moisture content. The shear strength of the palaeosol lowered to a very small value with continuous increase of shear rate, enabling the high mobility of the displaced landslide materials.

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Section: Setup Of Shear Testmentioning

confidence: 89%

Some fluidized landslides triggered by the 2011 Tohoku Earthquake (Mw 9.0), Japan

Wang¹,

Suemine²,

Zhang³

et al. 2014

Geomorphology

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“…4 The measurement of overground-openness in a given location (Yokoyama et al 1999). Set L and solve for h as shown in the figure (Chigira et al 2012). Thus, in factor (4), we calculated the Topographic Wetness Index, which reflects the topographical water collectability (Beven and Kirkby 1979).…”

Section: Methodology Of Hazard Zonationmentioning

confidence: 99%

Development of a Hazard Evaluation Technique for Earthquake-Induced Landslides Based on an Analytic Hierarchy Process (AHP) (IPL-154)

Higaki

Hamasaki

Hayashi³

2017

Advancing Culture of Living With Landslides

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In this study, we developed a hazard evaluation technique for earthquake-induced landslides that is based on topographical and geological factors extracted by an analytic hierarchy process (AHP). Several past earthquake cases that have caused multiple landslides in Japan were analyzed. With this method, through buffer movement analysis, we were able to obtain factor data on the respective sizes of terrain impacted by landslides and the magnitude of the landslides in the target area. In addition, we incorporated a method to provide predictive values for the evaluation through blunder probability analysis. The area distribution of the coherent landslides following the Mid-Niigata Prefecture Earthquake in 2004 corresponded well with the high-scoring areas derived by our evaluation model. This paper presents the results of the IPL project (IPL-154) titled "Development of a methodology for risk assessment of the earthquake-induced landslides".

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“…Many soils rich in halloysite are formed in a pyroclastic environment and landslides are commonly reported for these materials. Studies from Japan (Ishihara & Hsu, 1986;Chigira & Yokoyama, 2005;Chigira et al, 2012;Wang et al, 2014), Indonesia (Nakano et al, 2013), and New Zealand (Gulliver & Houghton, 1980;Keam, 2008;Tonkin & Taylor, 2011a,b) discuss landslides in soils containing halloysite. Many of these landslides begin as a planar slide failure, often along boundaries developed within the stratigraphy by depositional or weathering processes.…”

Section: A N D S L I D E Smentioning

confidence: 99%

“…As the material remoulds and moves downslope the landslides develop into flows which spread onto the depositional area (a complex slide-flow, Cruden & Varnes, 1996). They are characterized by high mobility, with apparent friction angles of ∼10-16° (Chigira et al, 2012). Typically these landslides are relatively small features (<100,000 m 3 ).…”

Section: A N D S L I D E Smentioning

confidence: 99%

“…Ishihara & Hsu (1986) reported on a number of landslide-inducing earthquake events in Japan and Italy, noting in particular that for the Nagano-seibu (Japan) earthquake of 1984, highly porous pumiceous silts containing halloysite were responsible for triggering large landslides. Chigira et al (2012) and Wang et al (2014) described a number of landslides triggered by the 2011 Tohoku Earthquake in Japan. Both describe slide-flow processes on gentle slopes (13-23°) with depths of 3-9 m and high mobility of the debris.…”

Section: A N D S L I D E Smentioning

confidence: 99%

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Halloysite behaving badly: geomechanics and slope behaviour of halloysite-rich soils

Moon

2016

Clay miner.

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Halloysite-rich soils derived fromin situweathering of volcanic materials support steep stable slopes, but commonly fail under triggers of earthquakes or rainfall. Resulting landslides are slideflow processes, ranging from small translational slides to larger rotational failures with scarps characteristic of sensitive soils. Remoulding of failed materials results in high-mobility flows with apparent friction angles of 10–16°. The materials characteristically have high peak-friction angles (∼25– 37°), low cohesion (∼12–60 kN m−2) and plasticity ( plasticity index ∼10–48%), and low dry bulk density (∼480–1,080 kg m−3) with small pores due to the small size of the halloysite minerals. They remain saturated under most field conditions, with liquidity indexes frequently >1. Remoulded materials have limited cohesion (<5 kN m−2) and variable residual friction angles (15°–35°). Halloysite mineral morphology affects the rheology of remoulded suspensions: tubular minerals have greater viscosity and undrained shear strength than spherical morphologies.

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Catastrophic Landslides of Pyroclastics Induced by the 2011 off the Pacific Coast of Tohoku Earthquake

Cited by 10 publications

References 10 publications

Some fluidized landslides triggered by the 2011 Tohoku Earthquake (Mw 9.0), Japan

Some fluidized landslides triggered by the 2011 Tohoku Earthquake (Mw 9.0), Japan

Development of a Hazard Evaluation Technique for Earthquake-Induced Landslides Based on an Analytic Hierarchy Process (AHP) (IPL-154)

Halloysite behaving badly: geomechanics and slope behaviour of halloysite-rich soils

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