The Morelia-Acambay fault System (MAFS), located in the central part of the Trans-Mexican Volcanic Belt (TMVB) is delimited by an active transtensive deformation zone associated with the oblique subduction zone between the Cocos and North American plates, with a convergence velocity of 55 mm/yr at the latitude of the state of Michoacán, México. Part of the oblique convergence is transferred to the central TMVB, just in the MAFS zone, where the slip rates range from 0.009 to 2.78 mm/year. The occurrence of great earthquakes like the Acambay earthquake (M s = 6.7) on November 19, 1912 with a 5 surface rupture, and in Maravatío, 1979 with M b = 5.3 are located into the MAFS. The zone is seismically active but with large periods of recurrence, as revealed by the seismic sequence (2.5 < M w <3.0) occurred near the city of Morelia in October 2007, with focal mechanisms corresponding to normal faulting with left-lateral components. Moreover, there are some paleoseismicanalyses showing quaternary movements of some faults with magnitudes between 6.0 -7.1M w . The purpose of this work is to probe an intrinsic definition of Active Faults for the MAFS as well as the estimation of possible maximum earthquake 10 magnitudes, in order to understand the dynamic of seismic activity along the MAFS. For the new fault dimensions and using three empirical relationships, we found a maximum magnitude of M w = 7. Additionally, a slip-rates series were compiled and analyzed, the results show a temporal strong persistence behavior and a high value of fractal dimension (D b = 1.86) related with a less concentration of small slip-rates. In other words, there is not an excess of the deformation in the MAFS in a single or restricted range of scales, and furthermore, this represents a migration of the ruptures to larger scales (3 length 38 km).
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