Video Experimental Relacionado
Updated: May 12, 2026
06:55
Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
Baja fuerza de la profundidad de la grieta de San Andrés de SAFOD en el núcleo central
David A Lockner1, Carolyn Morrow, Diane Moore
1US Geological Survey, Menlo Park, California 94025, USA. dlockner@usgs.gov
Nature
|March 29, 2011
Resumen
La Falla de San Andrés es sorprendentemente débil en profundidad debido a la arcilla saponita. Este hallazgo explica el movimiento rastrero de la falla, desafiando las teorías anteriores sobre la presión del fluido.
Área de la Ciencia:
- Geología Geología Geología.
- La tectónica es la tectónica.
- La mineralogía es la Mineralogía.
Sus antecedentes:
- La Falla de San Andrés exhibe un movimiento lateral derecho significativo entre las placas del Pacífico y América del Norte.
- Los distintos segmentos bloqueados y rastreros caracterizan la falla, con secciones bloqueadas que producen grandes terremotos.
Objetivo del estudio:
- Para investigar las propiedades mecánicas del núcleo de la Falla de San Andrés en profundidad.
- Para determinar los factores que controlan la deformación en la zona de arrastre de la falla.
Principales métodos:
- Medidas de fuerza de laboratorio de muestras de núcleos de falla obtenidas del Observatorio de la Falla de San Andrés en profundidad (SAFOD).
- Análisis de la composición mineral y condiciones in situ a una profundidad vertical de 2,7 km.
Principales resultados:
- La Falla de San Andrés en el sitio SAFOD es profundamente débil, con un bajo coeficiente de fricción (0,15).
- La debilidad se atribuye a la presencia de saponita, un mineral de arcilla de esmectita débil.
- La saponita se forma a partir de reacciones entre las rocas de la pared y la serpentinita, lo que indica un mecanismo de debilitamiento controlado por el mineral.
Conclusiones:
- La deformación en las secciones rastreras de la Falla de San Andrés está controlada por la presencia de minerales débiles como la saponita.
- Esto contrasta con las hipótesis anteriores que sugieren una alta presión del fluido como la causa principal de la debilidad de la falla.
- El estudio proporciona un modelo autoconsistente del estado de estrés de la falla, destacando la debilidad intrínseca en el sitio SAFOD.
Videos de Conceptos Relacionados
01:14Normal and Shear Force
When a beam is subjected to different loads, such as weight, pressure, or other external forces, internal forces are generated within the beam. These forces can have a significant impact on the overall stability and strength of the structure. Engineers use various methods to analyze and determine the magnitude and direction of these internal forces. One common technique used to determine internal forces in beams is the method of sections. This method involves considering an imaginary point or...
01:19Normal Stress
Normal stress is a type of stress that occurs when forces act perpendicular, or normal, to a material's cross-sectional area. This stress often arises in structures when subjected to axial loading, which is the application of force along the axis of an object. A practical example of this can be found in bridge truss members.
When a rod is under axial loading, the internal forces and corresponding stress are normal to the plane of the section, so it is termed normal stress. It's important to...
When a rod is under axial loading, the internal forces and corresponding stress are normal to the plane of the section, so it is termed normal stress. It's important to...
01:20Normal Strain under Axial Loading
Normal strain under axial loading is an important concept in the field of mechanics of materials. Axial loading implies the application of a force along the axis of a material, like a column or bar. This force can either compress or stretch the material. In the context of axial loading, normal strain is the deformation experienced by the material in the direction of the loading force. It's calculated as the change in length divided by the original length of the material. This unitless ratio...
01:18Fault Types
When analyzing a single line-to-ground fault from phase A to ground at a three-phase bus, it is important to consider the fault impedance. This impedance is zero for a bolted fault, equal to the arc impedance for an arcing fault, and represents the total fault impedance for a transmission-line insulator flashover. To derive sequence and phase currents, fault conditions are translated from the phase domain to the sequence domain.
For line-to-line faults occurring between phases B and C, the...
For line-to-line faults occurring between phases B and C, the...
01:23Lumber Defects
Lumber defects, which can affect both the appearance and structural integrity of wood, include a variety of growth and manufacturing flaws. Growth defects such as knots and knotholes occur where branches were once attached to the tree trunk, with knotholes forming when these knots fall out. Other natural defects include decay and insect damage, which compromise the wood's strength and durability.
Shakes are minor fractures that run along or across the wood's annual rings, while wane is...
Shakes are minor fractures that run along or across the wood's annual rings, while wane is...
01:12Non-destructive Tests for Concrete Strength
The rebound hammer test, also known as the Schmidt hammer test, is a non-destructive technique for evaluating the hardness of concrete and, indirectly, the strength of concrete. It operates on the principle that the rebound of a spring-driven mass from a concrete surface correlates to the surface's hardness. The device comprises a mass within a tubular housing, a spring mechanism, and a plunger that strikes the concrete. Upon release, the energy imparted to the mass by the spring causes it to...