Dictionary of Geotourism

2020 Edition
| Editors: Anze Chen, Young Ng, Erkuang Zhang, Mingzhong Tian

Asthenosphere

Reference work entry
DOI: https://doi.org/10.1007/978-981-13-2538-0_96

The asthenosphere is a secondary spherical layer in the upper-middle part of the upper mantle at depths of approximately 60–400 km. Inside the asthenosphere, the longitudinal and transverse wave speeds are significantly lower, so it is also called the low-speed layer. The asthenosphere is mainly composed of solid materials, but the rock strength is low, and the plasticity is high; therefore, it is easy to deform, and some scientists believe that the rock in the asthenosphere is molten. The asthenosphere is generally believed to be the source of magma for ultramafic rocks, and the lithosphere plates move above it.

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