| Title: | Effect of the lateral topographic density distribution on interpretational properties of Bouguer gravity maps |
| Other Titles: | Vliv laterálního modelu topografických hmot na interpretační vlastnosti map Bouguerovy tíže |
| Authors: | Rathnaya, Samurdhika Tenzer, Robert Pitoňák, Martin Novák, Pavel |
| Citation: | RATHNAYA, S., TENZER, R., PITOŇÁK, M., NOVÁK, P. Effect of the lateral topographic density distribution on interpretational properties of Bouguer gravity maps. Geophysical Journal International, 2020, roč. 220, č. 2, s. 892-909. ISSN 0956-540X. |
| Issue Date: | 2020 |
| Publisher: | Oxford University Press |
| Document type: | článek article |
| URI: | 2-s2.0-85086028356 http://hdl.handle.net/11025/38515 |
| ISSN: | 0956-540X |
| Keywords: | Teorie potenciálu;referenční systémy;družicová tíhová data |
| Keywords in different language: | Geopotential theory;reference systems;satellite gravity |
| Abstract: | Až donedávna byla informace o distribuci topografické hustoty omezena pouze na určité regiony a některé země, zatímco v globálním kontextu chyběla. UNB_TopoDens je první model, který poskytuje informace o laterální topografické hustotě po celém světě. Analýza tohoto modelu ukazuje, že průměrná topografická hustota pro celou kontinentální pevninu (s výjimkou polárních ledovců) je 2247 kg m-3. Tato hustota se významně liší od hodnoty 2670 kg m-3, která se obvykle používá pro znázornění kontinentální hustoty horních kůr. V této studii používáme model hustoty UNB_TopoDens ke kontrole, jak změny topografické hustoty ovlivňují interpretační vlastnosti Bouguerových tíhových dat. |
| Abstract in different language: | Until recently, the information about the topographic density distribution has been limited to only certain regions and some countries, while missing in the global context. The UNB_TopoDens is the first model that provides the information about a lateral topographic density globally. The analysis of this model also reveals that the average topographic density for the entire continental landmass (excluding polar glaciers) is 2247 kg m−3. This density differs significantly from the value of 2670 kg m−3 that is typically adopted to represent the continental upper crustal density. In this study, we use the UNB_TopoDens density model to inspect how the topographic density variations affect interpretational properties of Bouguer gravity maps. Since this model provides also the information about density uncertainties of individual lithologies (main rock types), we estimate the corresponding errors in the Bouguer gravity data. Despite a new estimate of the average topographic density corresponds to relative changes of ∼16 per cent in values of the topographic gravity correction, these changes do not affect interpretational properties of Bouguer gravity maps. The anomalous topographic density distribution (taken with respect to the average density of 2247 kg m−3), however, modifies the Bouguer gravity pattern. We demonstrate that the gravitational contribution of anomalous topographic density is globally mostly within ±25 mGal, but much large values are detected in Himalaya, Tibet, central Andes and along the East African Rift System. Our estimates also indicate that errors in the Bouguer gravity data attributed to topographic density uncertainties are mostly less than ±15 mGal, but in mountainous regions could reach large values exceeding even ±50 mGal. Unarguably, the UNB_TopoDens model provides an improved information about the global topographic density variations and their uncertainties. Nevertheless, much more in situ measurements of rock density samples together with detailed 3-D geological models are still necessary to understand better the actual density distribution within the whole topography, particularly to mention a density change with depth. |
| Rights: | Plný text není přístupný. © Oxford University Press |
| Appears in Collections: | Články / Articles (KGM) OBD |
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