Browsing by Author "Stein, Seth"

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    Decelerating Nazca-South America and Nazca-Pacific plate motions
    (American Geophysical Union, 1999) Norabuena Ortiz, Edmundo; Dixon, Timothy H.; Stein, Seth; Harrison, Christopher G. A.
    Space geodetic estimates of the rate of Nazca-South America convergence and Nazca-Pacific spreading averaging over several years show that present day rates are significantly slower than the 3 million year average NUVEL-1A model. The implied rates of deceleration are consistent with longer term trends extending back to at least 20 Ma, about the time of initiation of Andes growth, and may reflect consequences of ongoing subduction and construction of the Andes, e.g., increased friction and viscous drag on the subducted slab as the leading edge of South America thickens.
    Palabras clave:Space geodesyTectonic plateSubduction
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    Space geodetic observations of Nazca-South America convergence across the Central Andes
    (American Association for the Advancement of Science, 1998-01-16) Norabuena Ortiz, Edmundo; Leffler-Griffin, Lisa; Mao, Ailin; Dixon, Timothy; Stein, Seth; Selwyn Sacks, I.; Ocola, Leonidas; Ellis, Michael
    Space geodetic data recorded rates and directions of motion across the convergent boundary zone between the oceanic Nazca and continental South American plates in Peru and Bolivia. Roughly half of the overall convergence, about 30 to 40 millimeters per year, accumulated on the locked plate interface and can be released in future earthquakes. About 10 to 15 millimeters per year of crustal shortening occurred inland at the sub-Andean foreland fold and thrust belt, indicating that the Andes are continuing to build. Little (5 to 10 millimeters per year) along-trench motion of coastal forearc slivers was observed, despite the oblique convergence.
    Palabras clave:Collision zoneGeodesySpace geodesy