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This paper analyzes the methods used by the Princeton University Chapter of Engineers Without Borders to ensure the sustainability of a gravity-fed potable water system in rural northwestern Peru. While similar small scale development projects consider sustainability in their design process, some do not recognize the importance of an interdisciplinary approach to sustainability. This team, however, is inherently interdisciplinary in nature due to its unique subteam structure, which subsequently affects its approach to sustainability. By examining the technical, social, and financial considerations of the project conducted by the Princeton University Chapter of Engineers Without Borders, this paper argues for a three-pronged approach to sustainability. As can be seen through thoughtful design parameters, strong local partnerships, and strategic financial mechanisms, the project displays promise of future success with regards to sustainability. The main objective of the Princeton Chapter of Engineers Without Borders in this partnership is to ensure that the community has the knowledge, tools, and resources necessary to maintain the water system in a self-sufficient manner at the completion of the chapter's involvement. [ABSTRACT FROM AUTHOR]

Ancient DNA (aDNA) analysis provides a powerful means of investigating human migration, social organization, and a plethora of other crucial questions about humanity's past. Recently, specialists have suggested that the ideal research design involving aDNA would include multiple independent lines of evidence. In this paper, we adopt a transdisciplinary approach integrating aDNA with archaeological, biogeochemical, and historical data to investigate six individuals found in two cemeteries that date to the Late Horizon (1400 to 1532 CE) and Colonial (1532 to 1825 CE) periods in the Chincha Valley of southern Peru. Genomic analyses indicate that these individuals are genetically most similar to ancient and present-day populations from the north Peruvian coast located several hundred kilometers away. These genomic data are consistent with 16th century written records as well as ceramic, textile, and isotopic data. These results provide some of the strongest evidence yet of state-sponsored resettlement in the pre-Colonial Andes. This study highlights the power of transdisciplinary research designs when using aDNA data and sets a methodological standard for investigating ancient mobility in complex societies. [ABSTRACT FROM AUTHOR]

In the Nazca‐South American subduction zone, the subducted slab is flattened beneath northern Andes, called the Peruvian flat slab. The 2019 Mw 8.0 northern Peru intermediate‐depth normal‐faulting earthquake occurred at the leading edge of the Peruvian flat slab, where the slab rebends and sinks into greater depths. Here we investigate this earthquake by back projection analysis and finite fault inversion using seismic waveforms at teleseismic distances. The rupture process indicates that this earthquake ruptured mainly along strike (353°) ~150 km north‐northwestward within ~55 s (average rupture velocity ~2.7 km/s), resulting in two major slip areas with three high slip rate areas, which are consistent with three high‐frequency energy radiation subevents. Our study suggests that such a heterogeneous rupture may be caused by slab bending forces and dehydration embrittlement associated with morphology of the slab. Plain Language Summary: In the subduction zone, the oceanic plate and the continental plate converge, and then the oceanic plate subducts beneath the continental plate and sinks into great depths. In South America, the subducted oceanic plate is flattened beneath northern Peru instead of steeply sinking, called the Peruvian flat slab. After flattened, the oceanic plate starts to sink again. In the region where the oceanic plate starts to sink again, an earthquake with magnitude of 8.0 occurred at a depth of ~120 km on 26 May 2019. How and why this earthquake occurred at such a depth? Does the occurrence of this earthquake is related to the subducted oceanic plate? We try to answer these questions in this paper. By using two techniques, we obtained a scenario about this earthquake: In the region where the oceanic plate starts to sink again, the water in the oceanic plate releases, along with the effect of sinking to cause this earthquake. After this earthquake initiated, it ruptured mainly unilaterally north‐northwestward ~150 km with a speed of ~2.7 km/s, resulting in two large slip areas with three high slip rate areas. Such an uneven rupture may be produced by the heterogeneous structure of the slab. Key Points: Rupture process of the 26 May 2019 northern Peru earthquake is obtained from back projection analysis and finite fault inversionThe effects of slab bending forces and dehydration embrittlement together may cause this earthquake at an intermediate depthThis intermediate‐depth earthquake is probably associated with morphology of the Peruvian flat slab [ABSTRACT FROM AUTHOR]

In the Nazca‐South American subduction zone, the subducted slab is flattened beneath northern Andes, called the Peruvian flat slab. The 2019 Mw 8.0 northern Peru intermediate‐depth normal‐faulting earthquake occurred at the leading edge of the Peruvian flat slab, where the slab rebends and sinks into greater depths. Here we investigate this earthquake by back projection analysis and finite fault inversion using seismic waveforms at teleseismic distances. The rupture process indicates that this earthquake ruptured mainly along strike (353°) ~150 km north‐northwestward within ~55 s (average rupture velocity ~2.7 km/s), resulting in two major slip areas with three high slip rate areas, which are consistent with three high‐frequency energy radiation subevents. Our study suggests that such a heterogeneous rupture may be caused by slab bending forces and dehydration embrittlement associated with morphology of the slab. Plain Language Summary: In the subduction zone, the oceanic plate and the continental plate converge, and then the oceanic plate subducts beneath the continental plate and sinks into great depths. In South America, the subducted oceanic plate is flattened beneath northern Peru instead of steeply sinking, called the Peruvian flat slab. After flattened, the oceanic plate starts to sink again. In the region where the oceanic plate starts to sink again, an earthquake with magnitude of 8.0 occurred at a depth of ~120 km on 26 May 2019. How and why this earthquake occurred at such a depth? Does the occurrence of this earthquake is related to the subducted oceanic plate? We try to answer these questions in this paper. By using two techniques, we obtained a scenario about this earthquake: In the region where the oceanic plate starts to sink again, the water in the oceanic plate releases, along with the effect of sinking to cause this earthquake. After this earthquake initiated, it ruptured mainly unilaterally north‐northwestward ~150 km with a speed of ~2.7 km/s, resulting in two large slip areas with three high slip rate areas. Such an uneven rupture may be produced by the heterogeneous structure of the slab. Key Points: Rupture process of the 26 May 2019 northern Peru earthquake is obtained from back projection analysis and finite fault inversionThe effects of slab bending forces and dehydration embrittlement together may cause this earthquake at an intermediate depthThis intermediate‐depth earthquake is probably associated with morphology of the Peruvian flat slab [ABSTRACT FROM AUTHOR]

The southern rivers of Peru originate in the Andes Mountains and flow in a southwestern direction to the Pacific Ocean through one of the most hyper-arid regions of the world. During each sub-equatorial summer from December to February, rains and snow melt in the Andes increase the streamflow in these rivers, even as they pass through the 100 km arid zone to the ocean. This study quantified seasonal dynamics of 34 trace metal elements (TM) and other constituent concentrations in four southern river basins of Peru (Chili-Quilca, Tambo, Camana-Majes-Colca, and Ocoña) during 2019–2020. Consistent with previous studies, we observed that: (1) the river water in the southern basins had relatively high concentrations of B, As, Fe, Al, Mn, P, Pb and Ni, with As the most ubiquitous toxic TM in all the basins, often detected at concentrations surpassing Peruvian and USEPA regulated concentrations; and (2) basins with the most to least toxic TM contamination were the Tambo > Chili-Quilca > Camana-Majes-Colca > Ocoña. Seasonal streamflow strongly influenced the concentrations of twenty TM, with 15 TM (Al, Au, Ba, Cd, Co, Cu, Fe, Gd, Mn, Ni, P, Pb, Ti, Yb and Zr) consistently higher in the wet season, and with As, B, Ge, Li, and Pd higher in the dry season. Our results improve the understanding of seasonal variability and vulnerability in western Andes superficial water sources, which are highly influenced by both local geogenic and anthropogenic conditions. A Spanish translation of this paper is available in the online Supplementary Material. [Display omitted] • Arsenic is the most ubiquitous contaminant in surface waters of Southern Peru. • Al, Fe, As, B, Mn, P, Pb, and Ni exceeded the Peruvian water quality regulation. • Out of 34 metals studied, 14 showed a strong seasonal behavior (e.g., As, Pb and B). • Total recoverable metals trended better rather than dissolved metal with season. [ABSTRACT FROM AUTHOR]

This paper presents a case study in assessment of erosion hotspots in an Andean watershed. To do this, we made use of an interface called Geospatial Modelling of Soil Erosion (GEMSE): a tool that integrates Geographical Information Systems (GIS) with the Water Erosion Prediction Project (WEPP) model. Its advantages are: (i) it is independent of any special GIS software used to create maps and to visualize the results; (ii) the results can be used to produce response surfaces relating outputs (e.g. soil loss, runoff) with simple inputs (e.g. climate, soils, topography); (iii) the scale, resolution and area covered by the different layers can be different among them, which facilitates the use of different sources of information. The objective of this paper is to show GEMSE''s performance in a specific case study of soil erosion in La Encañada watershed (Peru) where the hillslope version of WEPP has been previously validated. Resulting runoff and soil loss maps show the spatial distribution of these processes. Though these maps do not give the total runoff and soil loss at the watershed level, they can be used to identify hotspots that will aid decision makers to make recommendations and plan actions for soil and water conservation. [Copyright &y& Elsevier]

This paper analyzes the material, discursive, and biophysical dimensions of fuelscapes, or energy landscapes. Ethnographic and ecological fieldwork was conducted in the Machu Picchu Historic Sanctuary, Peru. Andean land use studies have focused on agricultural patterns such as vertical production zones. Fuelscapes are an important, energy-based means of producing and representing landscape. They show how uncultivated lands fit into livelihood strategies and reflect historic sedimentation of landscape. Fuelscapes are shaped by ecological characteristics, historic settlement patterns and property rights, gendered and intergenerational divisions in household labor, and state conservation policies. Conservation policies delimit fuelscapes to privilege live trees, but the resultant denudation of dead wood may carry implications for ecosystem health. This study elucidates how official policies intersect with household and communal resource use strategies to produce Andean fuelscapes. It provides insight into how uncultivated ecosystems fit into land use politics, practices, and representation. [ABSTRACT FROM AUTHOR]

Archaeological research in the Andes has emphasized agriculture to the detriment of all other modes of production. A marked bias towards research on the coast, where crop farming predominates, and prejudices arising from the prevailing agro-centric perspective has given rise to a wealth of information concerning agricultural adaptations to this vertical environment. This paper seeks to redress the balance by investigating the precocious nature of agro-pastoralist traditions in the north-central highlands of Peru (ad 1000–1570). I challenge current ideas concerning the mainstay of subsistence in the Prehispanic high Andes that essentially emphasize farming to the detriment of other modes of production. Rather, I argue for a rich tableau of closely articulated groups of agro-pastoral and mixed farming communities ensconced in the kichwa , suni and puna areas of the cordillera. In these mixed communities the archaeological evidence suggests that it is the camelid herders who controlled and exercised power over the mixed farming communities with a concomitant specialization and intensification of the pastoralist economy. [ABSTRACT FROM AUTHOR]

Since 2010, as a result of the increased attention to quinoa as a highly nutritious crop and increased international demand, the acreage and production of quinoa expanded rapidly in the Andes region. Global demand and price increases create opportunities for smallholder Andean farmers but also concerns on the environmental impacts of quinoa acreage expansion and the changing quinoa production practices of smallholder farmers. In this paper, we assess the sustainability performance of smallholder quinoa production in the Junín region in the central highlands of Peru. We use primary data from a two-round survey among 367 smallholder farmers in the Junín region and secondary data from Ecoinvent and LCFoods databases. We use a combination of a life cycle assessment to assess the various environmental impacts of quinoa production; a data envelopment analysis to link the environmental performance of quinoa production with the economic performance, and quantify the eco-efficiency of individual farms; and a fractional regression model to examine the heterogeneity in eco-efficiency across farms. We find that conventional quinoa production creates a global warming potential of 7.82 kg CO 2 -equivalent per kg of protein, which is comparable to the environmental impact of organic quinoa production and production of other grain crops but much below the impact of production of rice and food from animal origin. Also, the eco-efficiency among smallholder quinoa producers is low, on average 18.2%, and that excessive use of mineral fertilizers and a switch to mechanical threshing explains this low eco-efficiency. We conclude that quinoa, with its specific nutritional characteristics, can make a contribution to a more sustainable global food production but that attention is needed to the soil fertility management practices of smallholder Andean farmers in order to reduce the environmental impact and increase the efficiency of smallholder quinoa production. [ABSTRACT FROM AUTHOR]