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Rapid source models of the 2021 Mw 7.4 Maduo, China, earthquake inferred from high-rate BDS3/2, GPS, Galileo and GLONASS observations / Jianfei Zang in Journal of geodesy, vol 96 n° 9 (September 2022)  

Public [article]  inJournal of geodesy > vol 96 n° 9 (September 2022) . - n° 58 Titre : Rapid source models of the 2021 Mw 7.4 Maduo, China, earthquake inferred from high-rate BDS3/2, GPS, Galileo and GLONASS observations Type de document : Article/Communication Auteurs : Jianfei Zang, Auteur ; Yangmao Wen, Auteur ; Zhicai Li, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 58 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Chine [Termes IGN] données GNSS [Termes IGN] magnitude [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] prévention des risques [Termes IGN] séisme [Termes IGN] temps réel [Termes IGN] tenseur Résumé : (auteur) On May 21, 2021, a Mw 7.4 earthquake struck the Maduo County in Qinghai province of China. The earthquake was well recorded by the surrounding high-rate Global Navigation Satellite System (GNSS) stations. In addition to GPS, GLONASS and BDS2 observations, these stations also recorded the latest BDS3 and Galileo observations. The performance of high-rate single-GNSS and fusion of multi-GNSS on warning magnitude calculation, rapid centroid moment tensor inversion and static fault slip inversion are well investigated in this study. The results demonstrate that within a short period of time (5 min), Precise Point Positioning (PPP) displacements of BDS3 alone are better than those of BDS2 alone, while the individual displacement accuracies of BDS3, GPS and Galileo are comparable. When BDS3 and BDS2 data are combined, the combined BDS accuracy is slightly better than that of GPS or Galileo alone. Compared with the single-GNSS displacements, the fusion of GPS + GLONASS + Galileo + BDS3/2 (GREC) can achieve the highest accuracy with standard deviation values of 0.25 cm, 0.22 cm and 0.53 cm in north, east and up components, respectively. For the warning magnitude estimation, BDS3 alone, BDS2 alone, combined BDS3/2, combined GPS + BDS3/2, Galileo alone and GREC all show comparable performance. The results of centroid moment tensor inversion and static fault slip inversion are related to the station distribution. When the same stations are used, the inverted centroid moment tensors and static fault slips of a single GNSS are very similar to the multi-GNSS inversion results, but the multi-GNSS centroid moment tensor series and fault slips appear to be more stable when the observation quality of a single GNSS such as GLONASS, is relatively low. The results obtained in this study imply that GPS, BDS3, Galileo and combined multi-GNSS have the potential to be used for the earthquake early warning and rapid earthquake source modeling. Numéro de notice : A2022-603 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01641-w Date de publication en ligne : 24/08/2022 En ligne : https://doi.org/10.1007/s00190-022-01641-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101556 [article]

Towards a 1 mGal accuracy and 1 min resolution altimetry gravity field / Lifeng Bao in Journal of geodesy, vol 87 n° 10-12 (October - December 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 10-12 (October - December 2013) . - pp 961 - 969 Titre : Towards a 1 mGal accuracy and 1 min resolution altimetry gravity field Type de document : Article/Communication Auteurs : Lifeng Bao, Auteur ; Houze Xu, Auteur ; Zhicai Li, Auteur Année de publication : 2013 Article en page(s) : pp 961 - 969 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] altimétrie satellitaire par radar [Termes IGN] champ de pesanteur terrestre [Termes IGN] géodésie marine [Termes IGN] gradient [Termes IGN] océanographie spatiale [Termes IGN] surface de la mer Résumé : (Auteur) Over the past three decades, radar altimetry has made a significant contribution to marine gravity field modeling. To improve the accuracy and resolution, we propose a new twin-satellite altimetry. Such a system has several advantages. Among others, it provides (i) twice the number of samples per time epoch, and (ii) information about the cross-track surface gradient with high accuracy because most of the environmental and tidal errors will be common to the simultaneous measurements and therefore cancel out when computing the cross-track gradient computation. We describe a rigorous procedure for the deduction of the sea surface gradient at each altimeter observation point (i.e., not only at the crossovers), from the twin-satellite altimetry system. The precision of the gradient will be slightly affected by orbit errors, instrument drift, and inaccuracies in the geophysical corrections to be applied. We also demonstrate that a 1 mGal accuracy and 1 min resolution marine altimetry gravity field can be obtained if certain conditions are met. To achieve the expected goal, we recommend an orbital configuration, phasing two satellites in 4-s time delay such that the Earth rotation creates a natural baseline between the two satellites, and a 18 kHz SAR altimeter. Numéro de notice : A2013-669 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0660-1 Date de publication en ligne : 25/09/2013 En ligne : https://doi.org/10.1007/s00190-013-0660-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32805 [article]

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