23 research outputs found

    Results from On-The-Ground Efforts to Promote Sustainable Cattle Ranching in the Brazilian Amazon

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    Agriculture in Brazil is booming. Brazil has the world’s second largest cattle herd and is the second largest producer of soybeans, with the production of beef, soybeans, and bioethanol forecast to increase further. Questions remain, however, about how Brazil can reconcile increases in agricultural production with protection of its remaining natural vegetation. While high hopes have been placed on the potential for intensification of low-productivity cattle ranching to spare land for other agricultural uses, cattle productivity in the Amazon biome (29% of the Brazilian cattle herd) remains stubbornly low, and it is not clear how to realize theoretical productivity gains in practice. We provide results from six initiatives in the Brazilian Amazon, which are successfully improving cattle productivity in beef and dairy production on more than 500,000 hectares of pastureland, while supporting compliance with the Brazilian Forest Code. Spread across diverse geographies, and using a wide range of technologies, participating farms have improved productivity by 30–490%. High-productivity cattle ranching requires some initial investment (R13006900/haorUS1300–6900/ha or US410–2180/ha), with average pay-back times of 2.5–8.5 years. We conclude by reflecting on the challenges that must be overcome to scale up these young initiatives, avoid rebound increases in deforestation, and mainstream sustainable cattle ranching in the Amazon

    Space‐Time Stress Variations on the Palu‐Koro Fault Impacting the 2018 Mw 7.5 Palu Earthquake and Its Seismic Hazards

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    Abstract In this study, we calculated the Coulomb stress change before and after the 2018 Palu earthquake (Mw 7.5) induced by historical large earthquakes on and around the Palu‐Koro fault (PKF) within Sulawesi Island, Indonesia. We found that the 1996 earthquake (Mw 7.9) on the Minahassa thrust likely promoted the 2018 Palu earthquake by stress loading on its hypocenter. Stress shadows in the PKF impacted the 2018 earthquake rupture’s southward unilateral propagation and termination. Stress increases in the two seismic gaps to the north and south ends of the PKF have resulted in increased seismic hazards, calling close attention to hazard prevention in central Sulawesi. This indicates that fault‐interaction‐induced stress variations on the PKF significantly controlled the 2018 Palu earthquake and its seismic hazards. Our study is important for understanding stress triggering between the subduction earthquakes and intraplate earthquakes in thrust and strike‐slip faults systems globally

    Triggered earthquakes suppressed by an evolving stress shadow from a propagating dyke

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    Large earthquakes can generate small changes in static stress: increases that trigger aftershock swarms, or reductions that create a region of reduced seismicity—a stress shadow1, 2. However, seismic waves from large earthquakes also cause transient dynamic stresses that may trigger seismicity3, 4. This makes it difficult to separate the relative influence of static and dynamic stress changes on aftershocks. Dyke intrusions do not generate dynamic stresses, so provide an unambiguous test of the stress shadow hypothesis. Here we use GPS and seismic data to reconstruct the intrusion of an igneous dyke that is 46 km long and 5 m wide beneath Bárðarbunga Volcano, central Iceland, in August 2014. We find that during dyke emplacement, bursts of seismicity at a distance of 5 to 15 km were first triggered and then abruptly switched off as the dyke tip propagated away from the volcano. We calculate the evolving static stress changes during dyke propagation and show that the stressing rate controls both the triggering and then suppression of earthquake rates in three separate areas adjacent to the dyke. Our results imply that static stress changes help control earthquake clustering. Similar small static stress changes may be important for triggering seismicity near geothermal areas, regions being hydrofractured and deflating oil and gas fields
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