The impact of extreme El Niño events on modern sediment transport along the western Peruvian Andes (1968–2012)

Morera, Sergio; Condom, Thomas; Crave, Alain; Steer, Philippe; Guyot, Jean‐Loup

doi:10.1038/s41598-017-12220-x

Cited by 43 publications

(34 citation statements)

References 64 publications

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“…Clearly, the general long-term accretion trends along the coastline of the Callao Bay were mainly due to the sediment discharge during an EN event, and thus Callao Bay was benefiting from the sediment input of big EN events to sustain its coastline. These results are in accordance with other studies that found that SSY in the Peruvian Andes increases significantly during extreme EN events [24], and in the case of the Rimac River, satellite image analysis of the shoreline suggest that this increased SSY is eventually deposited along the Callao Bay.…”

Section: Resultssupporting

confidence: 93%

“…For example, during the EN in 2017, discharge reached a maximum of 130 m 3 /s, which is two times the average historical value (Figure 3b). It is also shown that during extreme EN events, suspended sediment yield (SSY) of rivers in the Peruvian Andes increase to 30-60 times their average level of normal years [24]. During these events, 82%-97% of SSY occurs between January and April, which coincides with the summer season in the southern hemisphere [24].…”

Section: Introductionmentioning

confidence: 98%

“…It is also shown that during extreme EN events, suspended sediment yield (SSY) of rivers in the Peruvian Andes increase to 30-60 times their average level of normal years [24]. During these events, 82%-97% of SSY occurs between January and April, which coincides with the summer season in the southern hemisphere [24]. Therefore, the Rimac River provides a higher sediment supply during the summer seasons between January and April, and especially during those EN events where discharges increase significantly over normal conditions.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú

Guzmán

Ramos

Dastgheib

2020

JMSE

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Analyzing the long-term behavior of the coastlines in the vicinity of river mouths and estuaries usually relies on the mean (predicted) values of the sediment discharge from the river. However, this approach does not consider low frequency, severe events, such as El Niño (EN), that can have a large effect on coastlines. While the effects of an EN on flooding and droughts are well studied, little information exists about its effects on coastal zones, and especially on the evolution of coastlines. In early 2017, an EN occurred in the equatorial Pacific Ocean, and the country of Peru was affected with high precipitation levels, and extreme river discharges and flooding. During this event, in the district of Lima, the Rimac River discharged a huge amount of sediment into the Callao Bay, and the shoreline accreted approximately 1 km, demonstrating the significant effects that an EN can have on coastal zones. To explore these effects, this paper studies the influence of an EN on shoreline evolution in the Callao Bay by analyzing Landsat images from 1985-2019 to understand the shoreline evolution and identify changes to the coastline. Results show that when an extraordinary EN occurs (e.g., 1982-1983, 1997-1998, and 2017), the shoreline experiences high accretion compared to when a smaller, or no EN occurs. During these events, a significant delta forms at the south end of the bay, and the redistribution of the accumulated sediment by wave action causes the accretion of the adjacent coastlines for as far as 7 km north of the river mouth. This shows the importance of these events for the wellbeing of coastlines adjacent to river mouths affected by EN.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú

Guzmán

Ramos

Dastgheib

2020

JMSE

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“…Along the western flank of the Peruvian segment of the Central Andes, the cumulative seismic moment is greatest along the subduction interface and is thus below the coastline. This region does not coincide with the catchments yielding the highest decennial suspended sediments, which instead are located further inland, close to the main water divide (Morera et al, ). This observation, together with the restricted volume of coseismic landslides observed in a recent Andean megathrust earthquake (Lacroix et al, ), suggests a low catchment‐wide erosional response to this type of seismic event.…”

Section: Introductionmentioning

confidence: 95%

Suspended Sediments in Chilean Rivers Reveal Low Postseismic Erosion After the Maule Earthquake (Mw 8.8) During a Severe Drought

et al. 2019

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We address the question of whether all large‐magnitude earthquakes produce an erosion peak in the subaerial components of fluvial catchments. We evaluate the sediment flux response to the Maule earthquake in the Chilean Andes (Mw 8.8) using daily suspended sediment records from 31 river gauges. The catchments cover drainage areas of 350 to around 10,000 km2, including a wide range of topographic slopes and vegetation cover of the Andean western flank. We compare the 3‐ to 8‐year postseismic record of sediment flux to each of the following preseismic periods: (1) all preseismic data, (2) a 3‐year period prior to the seismic event, and (3) the driest preseismic periods, as drought conditions prevailed in the postseismic period. Following the earthquake, no increases in suspended sediment flux were observed for moderate to high percentiles of the streamflow distribution (mean, median, and ≥75th percentile). However, more than half of the examined stations showed increased sediment flux during baseflow. By using a Random Forest approach, we evaluate the contributions of seismic intensities, peak ground accelerations, co‐seismic landslides, hydroclimatic conditions, topography, lithology, and land cover to explain the observed changes in suspended sediment concentration and fluxes. We find that the best predictors are hillslope gradient, low‐vegetation cover, and changes in streamflow discharge. This finding suggests a combined first‐order control of topography, land cover, and hydrology on the catchment‐wide erosion response. We infer a reduced sediment connectivity due to the postseismic drought, which increased the residence time of sediment detached and remobilized following the Maule earthquake.

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“…These events have claimed more than 7,600 lives and affected more than 244,000 properties, of which approximately 60,000 were destroyed completely. HGE are common in the flanks of the mountain ranges and valleys and they are related to steep slopes, lithology, heavy rainfall, earthquakes, and an inadequate land use (Zavala and Núñez, ; Vargas et al, ; Villacorta et al, ; Margirier et al, ; Morera et al, ). Their origin is connected with the location of Peru in an active convergent boundary which determines the local geology and tectonic settings (Zavala and Núñez, ).…”

Section: Introductionmentioning

confidence: 99%

Linking atmospheric circulation patterns with hydro‐geomorphic disasters in Peru

Rodríguez-Morata

Ballesteros‐Cánovas

Rohrer

et al. 2018

Intl Journal of Climatology

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The occurrence of El Niño has been generally considered the main driver of hydro‐geomorphic processes in Peru. However, the climatic characterization of hydro‐geomorphic events (HGE) occurring in the absence of El Niño remains scarce. Information contained in the DesInventar disaster database suggests a widespread occurrence of HGE associated to cold‐neutral sea surface temperature (SST) in the central Pacific and south tropical Atlantic. Here, we aim at characterizing synoptic patterns associated with HGE that have occurred over last 35 years related to the different El Niño types and focusing as well on the non‐Niño phases. We use the ERA‐Interim reanalysis climate data and implement self‐organizing maps to assess the link between HGE in Peru and specific synoptic patterns. Results suggest that synoptic patterns associated with La Niña and neutral conditions play an important role in the occurrence of hydro‐geomorphic disasters in Peru during the austral summer. A total of 21% of the events are associated only with the 1972–1973, 1982–1983 and 1997–1998 El Niño events and are mainly focused in the northern Pacific coast of the country (i.e., Tumbes, Piura and Lambayeque) while more than 36% of the recorded events in the database were associated with La Niña and neutral conditions between 1970 and 2013. La Niña‐related events were more relevant in the Andean–Amazonian regions, whereas neutral conditions were related to more frequent HGEs in the southern regions (south of the 13.25°S) along the Peruvian Pacific coast. These outcomes imply an enhanced understanding of the synoptic mechanisms leading to the occurrence of HGE and contribute to a better understanding of the triggers of HGE causing disaster no exclusively related to El Niño‐like years in Peru.

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The impact of extreme El Niño events on modern sediment transport along the western Peruvian Andes (1968–2012)

Cited by 43 publications

References 64 publications

Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú

Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú

Suspended Sediments in Chilean Rivers Reveal Low Postseismic Erosion After the Maule Earthquake (Mw 8.8) During a Severe Drought

Linking atmospheric circulation patterns with hydro‐geomorphic disasters in Peru

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