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Note on Strain Release Variation with Depth


Title (Dublin Core)

Note on Strain Release Variation with Depth

Description (Dublin Core)

In the present paper an attempt is made to approach<br />the problem of the upper mantle structure by studying the strain<br />variation with depth. If the method and data used in this paper are adequate,<br />we may be allowed to say that although there is no strain release<br />evidence for the depth of the upper boundary of the asthenospliere zone on<br />account of lack of adequate accuracy in the determination of focal depths,<br />nevertheless there is ample indication of a discontinuity at about 125 km<br />depth. The abrupt change in the rate of decrease in the strain release<br />with depth near this level clearly indicates that a sudden decrease in the<br />yield strength of the material in the earth should occur at about this depth.<br />I t might even be possible to think that the melting point of some kind of<br />crystal grains or rocks in the earth is attained at that depth. However,<br />this does not involve a completely molten state. This state should rather<br />occur at depths where there is a complete lack of strain release. Regionally<br />this state is attained at different depths, but in some regions the partially<br />molten state, i. e. the heterogeneity of the mantle, probably recurs or increases<br />due to the pressure increase or some other reason and reaches a minor<br />maximum beyond which it might be possible to speculate that the heterogeneity<br />of the mantle falls off rapidly and a continuous layer of material<br />in molten state covers the whole earth. If data from other sources will<br />confirm this structure, there will be good reasons to think of redefining<br />the upper boundaries of surface and intermediate shocks at depths of 125<br />and 425 km or thereabouts, respectively.

Creator (Dublin Core)


Subject (Dublin Core)

Meteorology. Climatology
Geophysics. Cosmic physics

Publisher (Dublin Core)

Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Date (Dublin Core)


Type (Dublin Core)


Identifier (Dublin Core)


Source (Dublin Core)

Annals of Geophysics, Vol 17, Iss 3, Pp 337-352 (1964)

Language (Dublin Core)


Relation (Dublin Core)

Provenance (Dublin Core)

Journal Licence: CC BY