Análisis estructural de fallas potencialmente activas

Legorreta, Odranoel Quintero

doi:10.18268/bsgm2002v55n1a1

Cited by 4 publications

(4 citation statements)

References 4 publications

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“…The stress distribution in the zone shows that σ 3 is oriented NW-SE, σ 2 is oriented in NE-SW direction, and σ 1 is in vertical position, slightly displaced towards the horizontal (Figure 2b). Similar stress distribution was found in the Acambay-Tixmadejé fault (Martínez-Reyes and Nieto- Samaniego, 1990;García-Palomo et al, 2000;Suter et al, 2001;Quintero-Legorreta, 2002).…”

Section: Structural Analysissupporting

confidence: 75%

Evidence for quaternary seismic activity of the La Alberca-Teremendo fault, Morelia region, Trans-Mexican Volcanic Belt

Soria-Caballero¹,

Garduño‐Monroy²,

Alcalá³

et al. 2019

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The La Alberca-Teremendo fault is a 26 km-long, complex fault composed of an en échelon array of short crustal fault segments, belonging to the Morelia-Acambay fault system. This fault system shows parallel scarps with morphological evidence of recent activity such as drainage alteration, maximum throws of 50 m and minimum throws of 1.4 m that displace the recent soils. The fault acted as a conduit for the formation of the La Alberca de Guadalupe maar (23000 to 21000 years ago) and displaced afterwards its phreatomagmatic sequences. The paleoseismic analysis indicates that the La Alberca-Teremendo fault moved three times in the past 23000 years (age of the maar); this activity caused an average vertical displacement of 87 cm, and might have generated earthquakes with magnitudes Mw between 6.6 and 7, as well as volcano-tectonic earthquakes with magnitudes Mw between 4 and 5.5. The displacements were identified on the fault through the superposition of soils differentiated by a disconformity and an anomalous increase in the percentage of clay and organic matter. The La Alberca-Teremendo fault has dominant dip slip with a minor left-lateral component, a slip rate of 0.114 mm/year, and an average recurrence interval of 7726 ± 68 years. According to scaling relations that use the surface rupture length, if we assume that the La Alberca-Teremendo fault moves tectonically, it could generate earthquakes with maximum magnitudes of Mw between 6.7 and 7.3, however because of the active volcanic processes in the area, we could expect moderate volcano-tectonic earthquakes (Mw 4–5.5) rather than catastrophic ones.

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Section: Structural Analysissupporting

confidence: 75%

Evidence for quaternary seismic activity of the La Alberca-Teremendo fault, Morelia region, Trans-Mexican Volcanic Belt

Soria-Caballero¹,

Garduño‐Monroy²,

Alcalá³

et al. 2019

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“…This could have caused an increase of the water bodies level in this area causing them to get in contact, as was previously proposed for other lakes in Central Mexico [ 38 , 39 ]. The subsequent isolation of the ancestor of the two lineages that induced allopatric fragmentation, could have been the result of the end of the humid period, and/or the formation of a biogeographical barrier promoted by the geologic activity of the Penjamillo Graben [ 40 , 41 ], the Chapala-Tula fault or the activity and formation of the Corredor Tarasco volcanic field, which commenced during the Late Miocene-Early Pliocene [ 40 ] (Figure 1 ). This climatic change and the high tectonic activity have been proposed as the causes for the isolation of the palaeolakes along the TMVB during the Late Miocene-Pliocene (Figure 1 ) [ 38 ].…”

Section: Discussionmentioning

confidence: 99%

Evolutionary history of the endangered fish Zoogoneticus quitzeoensis (Bean, 1898) (Cyprinodontiformes: Goodeidae) using a sequential approach to phylogeography based on mitochondrial and nuclear DNA data

et al. 2008

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BackgroundTectonic, volcanic and climatic events that produce changes in hydrographic systems are the main causes of diversification and speciation of freshwater fishes. Elucidate the evolutionary history of freshwater fishes permits to infer theories on the biotic and geological evolution of a region, which can further be applied to understand processes of population divergence, speciation and for conservation purposes. The freshwater ecosystems in Central Mexico are characterized by their genesis dynamism, destruction, and compartmentalization induced by intense geologic activity and climatic changes since the early Miocene. The endangered goodeid Zoogoneticus quitzeoensis is widely distributed across Central México, thus making it a good model for phylogeographic analyses in this area.ResultsWe addressed the phylogeography, evolutionary history and genetic structure of populations of Z. quitzeoensis through a sequential approach, based on both microsatellite and mitochondrial cytochrome b sequences. Most haplotypes were private to particular locations. All the populations analysed showed a remarkable number of haplotypes. The level of gene diversity within populations was H¯d = 0.987 (0.714 – 1.00). However, in general the nucleotide diversity was low, π = 0.0173 (0.0015 – 0.0049). Significant genetic structure was found among populations at the mitochondrial and nuclear level (ΦST = 0.836 and FST = 0.262, respectively). We distinguished two well-defined mitochondrial lineages that were separated ca. 3.3 million years ago (Mya). The time since expansion was ca. 1.5 × 106 years ago for Lineage I and ca. 860,000 years ago for Lineage II. Also, genetic patterns of differentiation, between and within lineages, are described at different historical timescales.ConclusionOur mtDNA data indicates that the evolution of the different genetic groups is more related to ancient geological and climatic events (Middle Pliocene, ca. 3.3 Mya) than to the current hydrographic configuration of the basins. In general, mitochondrial and nuclear data supported the same relationships between populations, with the exception of some reduced populations in highly polluted basins (Lower Lerma River), where the effects of genetic drift are suggested by the different analyses at the nuclear and mitochondrial level. Further, our findings are of special interest for the conservation of this endangered species.

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“…There are two main biogeographic processes that are synchronous and congruent with the observed genetic patterns recovered in this study, suggesting that these events played an important role as the main drivers of diversification in the humboldtianum group. First, the allopatric fragmentation of clade I (Lake Chapala) from II–III (Lake Zacapu-Lakes Pátzcuaro and Zirahuén) may correspond to a biogeographical barrier promoted by the geologic activity of the Penjamillo Graben and the formation of the Tarascan corridor, which started much earlier during the Late Miocene–Early Pliocene [ 27 , 28 ]. These geological events separated the ancient corridors between the paleo Lerma-Chapala system and the Cuitzeo paleolake plus adjacent tributaries that connected Lakes Zacapu, Pátzcuaro, and Zirahuén [ 10 , 29 ].…”

Section: Discussionmentioning

confidence: 99%

Genome-wide species delimitation analyses of a silverside fish species complex in central Mexico indicate taxonomic over-splitting

et al. 2022

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Background Delimiting species across a speciation continuum is a complex task, as the process of species origin is not generally instantaneous. The use of genome-wide data provides unprecedented resolution to address convoluted species delimitation cases, often unraveling cryptic diversity. However, because genome-wide approaches based on the multispecies coalescent model are known to confound population structure with species boundaries, often resulting in taxonomic over-splitting, it has become increasingly evident that species delimitation research must consider multiple lines of evidence. In this study, we used phylogenomic, population genomic, and coalescent-based species delimitation approaches, and examined those in light of morphological and ecological information, to investigate species numbers and boundaries comprising the Chirostoma “humboltianum group” (family Atherinidae). The humboltianum group is a taxonomically controversial species complex where previous morphological and mitochondrial studies produced conflicting species delimitation outcomes. We generated ddRADseq data for 77 individuals representing the nine nominal species in the group, spanning their distribution range in the central Mexican plateau. Results Our results conflict with the morphospecies and ecological delimitation hypotheses, identifying four independently evolving lineages organized in three geographically cohesive clades: (i) chapalae and sphyraena groups in Lake Chapala, (ii) estor group in Lakes Pátzcuaro and Zirahuén, and (iii) humboltianum sensu stricto group in Lake Zacapu and Lerma river system. Conclusions Overall, our study provides an atypical example where genome-wide analyses delineate fewer species than previously recognized on the basis of morphology. It also highlights the influence of the geological history of the Chapala-Lerma hydrological system in driving allopatric speciation in the humboltianum group.

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Análisis estructural de fallas potencialmente activas

Cited by 4 publications

References 4 publications

Evidence for quaternary seismic activity of the La Alberca-Teremendo fault, Morelia region, Trans-Mexican Volcanic Belt

Evidence for quaternary seismic activity of the La Alberca-Teremendo fault, Morelia region, Trans-Mexican Volcanic Belt

Evolutionary history of the endangered fish Zoogoneticus quitzeoensis (Bean, 1898) (Cyprinodontiformes: Goodeidae) using a sequential approach to phylogeography based on mitochondrial and nuclear DNA data

Genome-wide species delimitation analyses of a silverside fish species complex in central Mexico indicate taxonomic over-splitting

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