The Share of Landslides in the Occurrence of Natural Hazards and the Significance of El Niño in the Cordillera Blanca and Cordillera Negra Mountains, Peru

Vilímek, Vít; Hanzlík, Josef; Sládek, Ivan; Šandov, Milada; Santillán, Nelson

doi:10.1007/978-3-642-22087-6_9

Cited by 10 publications

(11 citation statements)

References 11 publications

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“…For example, [44] found regional correlations between 0.58 and 0.78, considering the stations in the cities of Trujillo, Chiclayo, and Piura. Similarly, a review of the homogeneous landslide database DesInventar for the area of the Ancash Department (Peru) showed a major correlation of landslides with El Niño episodes (41% of all the recorded catastrophes) between 1971 and 2009 [42]. More recently, multiple regions located on the coast of northern Peru were seriously affected by floods during the first three months of 2017 with the increasing SST yield in the El Niño of 2017 [45].…”

Section: Enso (El Niño Southern Oscillation)mentioning

confidence: 99%

“…In Peru, the natural hazards are more frequent in coastal areas and in the Cordillera Occidental and Cordillera Central, decreasing as one goes inland [42]. Despite the hyper-arid coastal climate of northern Peru, the authors of [43,44] concluded that the region around the city of Trujillo experiences some of the strongest ENSO signals associated with increases in rainfall, typically exceeding 40%.…”

Section: Enso (El Niño Southern Oscillation)mentioning

confidence: 99%

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Characteristics of Rainfall Events Triggering Landslides in Two Climatologically Different Areas: Southern Ecuador and Southern Spain

2020

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In the research field on landslide hazard assessment for natural risk prediction and mitigation, it is necessary to know the characteristics of the triggering factors, such as rainfall and earthquakes, as well as possible. This work aims to generate and compare the basic information on rainfall events triggering landslides in two areas with different climate and geological settings: the Loja Basin in southern Ecuador and the southern part of the province of Granada in Spain. In addition, this paper gives preliminary insights on the correlation between these rainfall events and major climate cycles affecting each of these study areas. To achieve these objectives, the information on previous studies on these areas was compiled and supplemented to obtain and compare Critical Rainfall Threshold (CRT). Additionally, a seven-month series of accumulated rainfall and mean climate indices were calculated from daily rainfall and monthly climate, respectively. This enabled the correlation between both rainfall and climate cycles. For both study areas, the CRT functions were fitted including the confidence and prediction bounds, and their statistical significance was also assessed. However, to overcome the major difficulties to characterize each landslide event, the rainfall events associated with every landslide are deduced from the spikes showing uncommon return periods cumulative rainfall. Thus, the method used, which has been developed by the authors in previous research, avoids the need to preselect specific rainfall durations for each type of landslide. The information extracted from the findings of this work show that for the wetter area of Ecuador, CRT presents a lower scale factor indicating that lower values of accumulated rainfall are needed to trigger a landslide in this area. This is most likely attributed to the high soil saturation. The separate analysis of the landslide types in the case of southern Granada show very low statistical significance for translational slides, as a low number of data could be identified. However, better fit was obtained for rock falls, complex slides, and the global fit considering all landslide types with R2 values close to one. In the case of the Loja Basin, the ENSO (El Niño Southern Oscillation) cycle shows a moderate positive correlation with accumulated rainfall in the wettest period, while for the case of the south of the province of Granada, a positive correlation was found between the NAO (North Atlantic Oscillation) and the WeMO (Western Mediterranean Oscillation) climate time series and the accumulated rainfall. This correlation is highlighted when the aggregation (NAO + WeMO) of both climate indices is considered, reaching a Pearson coefficient of –0.55, and exceeding the average of the negative values of this combined index with significant rates in the hydrological years showing a higher number of documented landslides.

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Section: Enso (El Niño Southern Oscillation)mentioning

confidence: 99%

Section: Enso (El Niño Southern Oscillation)mentioning

confidence: 99%

Characteristics of Rainfall Events Triggering Landslides in Two Climatologically Different Areas: Southern Ecuador and Southern Spain

2020

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“…Earthquakes and prolonged or intense precipitation events are the most significant landslide triggers to be considered for the study site (Plafker et al, 1971;Vilímek et al, 2012). The regional seismicity has its major source in the subduction process of the Nazca plate beneath the South American tectonic plate.…”

Section: Description Of the Selected Environmental Conditionsmentioning

confidence: 99%

Paraglacial Rock Slope Stability Under Changing Environmental Conditions, Safuna Lakes, Cordillera Blanca Peru

Klimeš

Novotný

Rapre³

et al. 2021

Front. Earth Sci.

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Landslides or landslide-induced impact waves in high mountain lakes represent a high hazard for society, calling for realistic assessments of rock slope stability responsible for the process chain initiation. This task is often hampered by complex interplays of triggers, which effects on slope stability may be delayed by decades or even millennia, while historical records describing slope topography or landslide occurrences are usually shorter and incomplete. This article builds on rarely available detailed historical data describing the site of the 2002 rock avalanche in the Cordillera Blanca, Peru. It caused a dangerous impact wave in the Safuna Alta Lake resulting in a minor flood, but ongoing downstream development significantly increased the risk of a comparable event. Pre-2002 and post-2002 failure slope topography, 70 years long history of glaciation and landslide occurrences were combined with non-invasive field geological surveys and laboratory geotechnical analyses to characterize the distinct morphological parts of the failed slope with reliable engineering geological slope models. Slope stability was calculated for a series of environmental scenarios providing insights into the 2002 rock avalanche failure mechanism and dynamics as well as the role of glacier slope support for its stability. Results show that the rock slope stability is governed by discontinuous slip planes where rock bridges represent the most likely additional resisting forces. The effect of glacier support on the slope stability is limited under full-water saturation of the rocks and due to specific morpho-structural conditions. Importance of the long-term, progressive deterioration of the rock slope strength under paraglacial environment and repeated seismic shaking is illustrated by the fact that even the Little Ice Age maximum glacier extend only had minor positive effect on the pre-2002 rock avalanche slope stability. Despite of that, the slope remained without a major failure for decades or possibly even centuries. Its collapse in 2002 caused retrogressive movements of the adjacent slope, which remains highly unstable until now. Therefore the future safety of the lake would largely benefit from the implementation of a reliable slope movement monitoring system.

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“…Medina, 1991), destroying rock formations raised by internal geodynamics and dragging debris to lower places (Fan et al, 2018;Tarbuck & Lutgens, 2005). These types of events frequently occur in mountainous areas, caused mainly by intense rainfall, cycles of freezing and thawing of glaciers (Oliver-Smith, 2014; Vit Vilímek et al, 2013), by earthquakes (Balzano et Vilímek et al, 2014). Depending on the atmospheric agent that originates it and the factors that intervene in its development, they can be classi ed into mass gravitational movements, water ows ( ood), snow avalanches, wind, littoral, coastal and glacial erosion (Lario & Bardají, 2017; J.…”

Section: Introductionmentioning

confidence: 99%

Space-Temporary Analysis of External Geodynamic Disasters Occurred in Huaraz Province, Ancash - Peru

Malca

Joaquin

Tello

et al. 2021

Preprint

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The natural disasters generated by external geodynamics are geological risks that constantly modify landscapes, with a more significant occurrence in mountainous areas, affecting populations and registering many victims in densely populated places. This research analyzes the events in Huaraz province, of Ancash department, in the central Andes of Peru, to find relationships between their occurrence and geographical factors such as altitude, slopes, climate, and extreme meteorological events. An inventory of events was made and classified as floods, mass gravitational movements, waterlogging or snow avalanches. Using QGIS software, spreadsheets and digital elevation models, information on natural disasters, altitude levels, physiography, river basins, meteorological data, and earthquakes were analyzed. As a result, it was obtained that the Quechua region registered 60% of all events; the Santa River basin 76%; the wet season of the Peruvian Andes 78%; and places with slopes between 8% and 50% (wavy relief) 72% of disasters. It is concluded that the best conditions for these events are the intense rainfall and the undulating reliefs, predominant in the Quechua region. Likewise, floods are the disasters that register the most significant number and generate the most damage in Huaraz province. Finally, it was determined that high-intensity El Niño-Southern Oscillation processes do not necessarily increase the number of events for the study area.

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The Share of Landslides in the Occurrence of Natural Hazards and the Significance of El Niño in the Cordillera Blanca and Cordillera Negra Mountains, Peru

Cited by 10 publications

References 11 publications

Characteristics of Rainfall Events Triggering Landslides in Two Climatologically Different Areas: Southern Ecuador and Southern Spain

Characteristics of Rainfall Events Triggering Landslides in Two Climatologically Different Areas: Southern Ecuador and Southern Spain

Paraglacial Rock Slope Stability Under Changing Environmental Conditions, Safuna Lakes, Cordillera Blanca Peru

Space-Temporary Analysis of External Geodynamic Disasters Occurred in Huaraz Province, Ancash - Peru

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