The genesis of tangential mass forces in lithospheric plates, and their role in geodynamics

• Main Authors: Ребецкий Ю.Л., Мягков ДС.
• Format: Article
• Language: Russian
• Published: Institute of Volcanology and Seismology FEB RAS 2020-10-01
• Series: Вестник Камчатской региональной ассоциации "Учебно-научный центр". Серия: Науки о Земле
• Subjects: geodynamics; physical surface of the earth; geoid; tangential mass forces
• Online Access: http://www.kscnet.ru/journal/kraesc/article/view/629

The problem of determining small tangential mass forces in the Earth lithosphere is formulated. It is shown that the current state in understanding the shape of The Earth's physical surface and data on its geoid allow us to determine deviations of the vertical line from the normal to the Earth's surface on the scale of averaging in the first hundreds of kilometers. It is established that for large areas of lithospheric plates, systematic unidirectional deviations of the vertical line from the normal to the surface are observed. Small tangential mass forces calculated from these data are of the order n 10–4 G/cm3. If there is a stable surface gradient over areas of the first thousand kilometers (the oceanic part of the lithospheric plates) tangential mass forces can create additional compressive or tensile horizontal stresses of the order of 10–15 MPa. These forces, summed up by the depth of the lithosphere, are able to overcome the level of tangential stresses of 0.2–0.3 MPa at its bottom, and therefore they can be considered as a source of plate motion.