Western US intraplate deformation controlled by the complex lithospheric structure

The western United States is one of Earth's most tectonically active regions, characterized by extensive crustal deformation through intraplate earthquakes and geodetic motion. Such intracontinental deformation is usually ascribed to plate boundary forces, lithospheric body forces, and/or viscous drag from mantle flow. However, their relative importance in driving crustal deformation remains controversial due to inconsistent assumptions on crustal and mantle structures in prior estimations. Here, we utilize a fully dynamic three-dimensional modeling framework with data assimilation to simultaneously compute lithospheric and convective mantle dynamics within the western United States. This approach allows for quantitative estimations of crustal deformation while accounting for the realistic three-dimensional lithospheric structure. Our results show the critical role of the complex lithospheric structure in governing intraplate deformation. Particularly, the interaction between the asthenospheric flow and lithospheric thickness step along the eastern boundary of the Basin and Range represents a key driving mechanism for localized crustal deformation and seismicity.

Cell Factories for Industrial Production Processes: Current Issues and Emerging Solutions

Despite all the progresses made by metabolic engineering, still only a few biotechnological processes are running at an industrial level. In order to boost the biotechnological sector, integration strategies as well as long-term views are needed. The aim of the present review is to identify the main drawbacks in biotechnological processes, and to propose possible solutions to overcome the issues in question. Novel cell factories and bioreactor design are discussed as possible solutions. In particular, the following microorganisms: Yarrowia lipolytica, Trichosporon oleaginosus, Ustilago cynodontis, Debaryomyces hansenii along with sequential bioreactor configurations are presented as possible cell factories and bioreactor design solutions, respectively.

Bridging the connection between effective viscosity and electrical conductivity through water content in the upper mantle

Upper mantle viscosity plays a key role in understanding plate tectonics and is usually extrapolated from laboratory-based creep measurements of upper mantle conditions or constrained by modeling geodetic and post-seismic observations. At present, an effective method to obtain a high-resolution viscosity structure is still lacking. Recently, a promising estimation of effective viscosity was obtained from a transform derived from the results of magnetotelluric imaging. Here, we build a relationship between effective viscosity and electrical conductivity in the upper mantle using water content. The contribution of water content to the effective viscosity is isolated in a flow law with reference to relatively dry conditions in the upper mantle. The proposed transform is robust and has been verified by application to data synthesized from an intraoceanic subduction zone model. We then apply the method to transform an electrical conductivity cross-section across the Yangtze block and the North China Craton. The results show that the effective viscosity structure coincides well with that estimated from other independent datasets at depths of 40 to 80 km but differs slightly at depths of 100 to 200 km. We briefly discussed the potentials and associated problems for application.

Imaging the distribution of transient viscosity after the 2016 Mw 7.1 Kumamoto earthquake

The deformation of mantle and crustal rocks in response to stress plays a crucial role in the distribution of seismic and volcanic hazards, controlling tectonic processes ranging from continental drift to earthquake triggering. However, the spatial variation of these dynamic properties is poorly understood as they are difficult to measure. We exploited the large stress perturbation incurred by the 2016 earthquake sequence in Kumamoto, Japan, to directly image localized and distributed deformation. The earthquakes illuminated distinct regions of low effective viscosity in the lower crust, notably beneath the Mount Aso and Mount Kuju volcanoes, surrounded by larger-scale variations of viscosity across the back-arc. This study demonstrates a new potential for geodesy to directly probe rock rheology in situ across many spatial and temporal scales.

Constraining lithospheric flow

Geophysical data help to determine the viscosity of Earth's crust and upper mantle