Dataset Information

Repeating microearthquake sequences interact predominantly through postseismic slip.

ABSTRACT: Studying small repeating earthquakes enables better understanding of fault physics and characterization of fault friction properties. Some of the nearby repeating sequences appear to interact, such as the 'San Francisco' and 'Los Angeles' repeaters on the creeping section of the San Andreas Fault. It is typically assumed that such interactions are induced by static stress changes due to coseismic slip. Here we present a study of the interaction of repeating earthquakes in the framework of rate-and-state fault models using state-of-the-art simulation methods that reproduce both realistic seismic events and long-term earthquake sequences. Our simulations enable comparison among several types of stress transfer that occur between the repeating events. Our major finding is that postseismic creep dominates the interaction, with earthquake triggering occurring at distances much larger than typically assumed. Our results open a possibility of using interaction of repeating sequences to constrain friction properties of creeping segments.

SUBMITTER: Lui SK

PROVIDER: S-EPMC5059473 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Repeating microearthquake sequences interact predominantly through postseismic slip.

Lui Semechah K Y SK Lapusta Nadia N

Nature communications 20161005

Studying small repeating earthquakes enables better understanding of fault physics and characterization of fault friction properties. Some of the nearby repeating sequences appear to interact, such as the 'San Francisco' and 'Los Angeles' repeaters on the creeping section of the San Andreas Fault. It is typically assumed that such interactions are induced by static stress changes due to coseismic slip. Here we present a study of the interaction of repeating earthquakes in the framework of rate-a ...[more]

PMID: 27703151

Similar Datasets

Project description:Mutational hotspots offer significant sources of genetic variability upon which selection can act. However, with a few notable exceptions, we know little about the dynamics and fitness consequences of mutations in these regions. Here, we explore evolutionary forces shaping homopolymeric tracts that are especially vulnerable to slippage errors during replication and transcription. Such tracts are typically eliminated by selection from most bacterial sequences, yet persist in genomes of endosymbionts with small effective population sizes (N(e)) and biased base compositions. Focusing on Blochmannia, a bacterial endosymbiont of ants, we track the divergence of genes that contain frameshift mutations within long (9-11 bp) polyA or polyT tracts. Earlier experimental work documented that transcriptional slippage restores the reading frame in a fraction of messenger RNA molecules and thereby rescues the function of frameshifted genes. In this study, we demonstrate a surprising persistence of these frameshifts and associated tracts for millions of years. Across the genome of this ant mutualist, rates of indel mutation within homopolymeric tracts far exceed the synonymous mutation rate, indicating that long-term conservation of frameshifts within these tracts is inconsistent with neutrality. In addition, the homopolymeric tracts themselves are more conserved than expected by chance, given extensive neutral substitutions that occur elsewhere in the genes sampled. These data suggest an unexpected role for slippage-prone DNA tracts and highlight a new mechanism for their persistence. That is, when such tracts contain a frameshift, transcriptional slippage plays a critical role in rescuing gene function. In such cases, selection will purge nucleotide changes interrupting the slippery tract so that otherwise volatile sequences become frozen in evolutionary time. Although the advantage of the frameshift itself is less clear, it may offer a mechanism to lower effective gene expression by reducing but not eliminating transcripts that encode full-length proteins.

Project description:BackgroundMycoplasmas-contamination of Orientia tsutsugamushi, one of the obligated intracellular bacteria, is a very serious problem in in vitro studies using cell cultures because mycoplasmas have significant influence on the results of scientific studies. Only a recommended decontamination method is to passage the contaminated O. tsutsugamushi strains through mice to eliminate only mycoplasmas under influence of their immunity. However, this method sometimes does not work especially for low virulent strains of O. tsutsugamushi which are difficult to propagate in mice. In this study, we tried to eliminate mycoplasmas contaminants from both high virulent and low virulent strains of the contaminated O. tsutsugamushi by repeating passage through cell cultures with antibiotics in vitro.ResultsWe cultured a contaminated, high virulent strain of O. tsutsugamushi using a mouse lung fibroblasts cell line, L-929 cell in the culture medium containing lincomycin at various concentrations and repeated passages about every seven days. At the passage 5 only with 10 μg/ml of lincomycin, we did not detect mycoplasmas by two PCR based methods whereas O. tsutsugamushi continued good growth. During following four passages without lincomycin, mycoplasmas did not recover. These results suggested that mycoplasmas were completely eliminated from the high virulent strain of O. tsutsugamushi. Furthermore, by the same procedures with 10 μg/ml of lincomycin, we also eliminated mycoplasmas from a contaminated, low virulent strain of O. tsutsugamushi. Our additional assay showed that 50 μg/ml of lyncomycin did not inhibit the growth of O. tsutsugamushi, although MICs of many mycoplasmas contaminants were less than 6 μg/ml as shown previously.ConclusionOur results showed an alternative method to eliminate mycoplasmas from the contaminated O. tsutsugamushi strains in place of in vivo passage through mice. Especially this notable method works for the decontamination not only from the high virulent strain also from the low virulent strain of O. tsutsugamushi. For further elimination, lincomycin at the limit concentration, which does not inhibit the growth of O. tsutsugamushi, can possibly eliminate most mycoplasmas from contaminated O. tsutsugamushi strains.

Dataset Information

Repeating microearthquake sequences interact predominantly through postseismic slip.

Publications

Repeating microearthquake sequences interact predominantly through postseismic slip.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets