[J08-P] Poster

[J08-P-19] The shallow structure of Tatun Volcano Group from residual gravity and magnetic data

^○Hsien-Hsiang Hsieh^{1, 2, 3}, Benjamin Fong Chao¹, Horng-Yuan Yen⁴ (1.Academia Sinica, Taipei, Taiwan, 2.NCREE, Taiwan, 3.E-TEC, National Dong Hwa University, Taiwan, 4.National Central University, Taiwan)

Tatun Volcano Group (TVG) is composed by 21 volcanoes, located in northern Taiwan. It is a very important topic to understand the background of volcano group, especially which is nearby Taipei city, the largest city in Taiwan. In this study, the new magnetic surveys (372 points) and gravity data combinations (246 points) of TVG are processing. After data processing and correction, new gravity and magnetic anomaly maps are showed. The anomaly maps are fitting well with volcanic and igneous rocks. For modeling TVG structures near shallow surface, the filters are used to show the regional and residual map from the gravity and magnetic maps. The gravity inversion and magnetic analyses are also used in the next step. Final, in the gravity results, TVG is covered by high density andesitic lavas, especially around two major peaks (Tatun and Chihsing Mts.). The Curie Point Depth in TVG from magnetic data also provide the high thermal gradient area beneath Tatun and Chihsing Mts.