Principle and geomorphological applicability of summit level and base level technique using Aster Gdem satellite-derived data and the original software Baz

Akihisa Motoki, Kenji Freire Motoki, Susanna Eleonora Sichel, Samuel da Silva, José Ribeiro Aires


This article presents principle and geomorphological applicability of summit level technique using Aster Gdem satellite-derived topographicdata. Summit level corresponds to thevirtualtopographic surface constituted bylocalhighest points, such as peaks and plateau tops, and reconstitutes palaeo-geomorphology before the drainage erosion. Summit level map is efficient for reconstitution of palaeo-surfaces and detection of active tectonic movement. Base level is thevirtualsurface composed oflocallowest points, as valley bottoms. The difference between summit level and base level is called relief amount. Thesevirtualmapsareconstructed by theoriginalsoftwareBaz. Themacroconcavity index, MCI, is calculated from summit level and relief amount maps. The volume-normalised three-dimensional concavity index, TCI, is calculated from hypsometric diagram. The massifs with high erosive resistance tend to have convex general form and low MCI and TCI. Those with low resistance have concave form and high MCI and TCI. The diagram of TCI vs. MCI permits to distinguish erosive characteristics of massifs according to their constituent rocks. The base level map for ocean bottom detects the basement tectonic uplift which occurred before the formation of the volcanic seamounts.



summit level; base level; morphological analyses; palaeo-surface; erosive resistance; active fault.

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ISSN 1806-2563 (impresso) e ISSN 1807-8664 (on-line) e-mail:


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