Michael Rilee

and 8 more

D. Sarah Stamps

and 10 more

The EarthCube BALTO broker (Brokered Alignment of Long-Tail Observations) provides streamlined access to both long-tail and big data using Web Services through several distinct mechanisms. First, we updated the OPeNDAP framework Hyrax, software that serves big data from USGS, NASA, and other sources, with a BALTO extension that tags dataset landing pages with JSON-LD encoding automatically. Therefore, the big data made available through Hyrax are now searchable via EarthCube GeoCODES (formerly P418) and Google Dataset Search. The BALTO broker extension to Hyrax makes thousands of datasets easily searchable and accessible. Second, we focused our efforts on a geodynamics use-case aimed at advancing our understanding of continental rifting processes through the use of an NSF mantle convection code called ASPECT. By addressing this use-case, we implemented a web services brokering capability in ASPECT that allows for remotely accessing datasets via a URL defined in an ASPECT parameter file. Third, through another use-case in ASPECT aimed at testing hypotheses involving global mantle flow, we developed a brokering mechanism for a “plug-in” that accesses NetCDF seismic tomography data from the NSF seismology facility IRIS, then transforms it into the format needed by ASPECT to run global mantle flow models constrained by seismic tomography. Fourth, we demonstrate methods to allow any scientist or citizen scientist to make their in-situ IoT based sensor data collection efforts available to the world. Finally, we are developing a Jupyter Notebook with a GUI that allows for users to search Hyrax servers for big datasets and long-tail data. These cyberinfrastructure developments comprise the entire EarthCube BALTO brokering capabilities.

Emmanuel A. Njinju

and 3 more

The Rungwe Volcanic Province (RVP) is a volcanic center in an anomalous region of magma-assisted rifting positioned within the magma-poor Western Branch of the East African Rift (EAR). The source of asthenospheric melt for the RVP is enigmatic, particularly since the volcanism is highly localized, unlike the Eastern Branch of the EAR. Some studies suggest the source of asthenospheric melt beneath the RVP arises from thermal perturbations in the upper mantle associated with an offshoot of the African Superplume flowing from the SW, while others propose a similar mechanism, but from the Kenyan plume diverted around the Tanzania Craton from the NE. Another possibility is decompression melting from upwelling asthenosphere due to lithospheric modulated convection (LMC) where the lithosphere is thin. We test the hypothesis that asthenospheric melt feeding the RVP can be generated from LMC. We develop a 3D thermomechanical model of LMC beneath the RVP and the entire Malawi Rift that incorporates melt generation. We assume a rigid lithosphere with laterally varying thickness and use non-Newtonian, temperature-, pressure- and porosity-dependent creep laws of anhydrous peridotite for the sublithospheric convecting mantle. We find decompression melt associated with LMC upwelling (~3 cm/yr) occurs at a maximum depth of ~150 km localized beneath the RVP. We also suggest asthenospheric upwelling due to LMC entrains plume materials that do not penetrate the transition zone into the melt. Decompression melting associated with upwelling due to LMC may also provide melt sources for other continental regions of thinned lithosphere.

Kodi Neumiller

and 3 more

ASPECT (Advanced Solver for Problems in Earth’s ConvecTion) is an analysis tool that simulates convection in the Earth’s mantle and other planets. The BALTO project has extended the ASPECT software so it can read data used to perform the simulations from the BALTO brokering server. These additions to the ASPECT codebase allow data to be remotely accessed and then processed as if the data were stored on the user’s local computer. The additions to ASPECT can be split into two distinct sections: a URL reader and a netCDF reader/translator. The URL reader uses the Data Access Protocol (DAP) to access remote data from supported web servers. Data values are transferred from the BALTO broker and converted within the URL reader plugin to match the format that is expected by the rest of the ASPECT code. Similarly, the netCDF plugin reads data stored using netCDF from the BALTO broker and transforms these data into the sph file format required by ASPECT to perform global mantle convection. The netCDF plugin can use either local or remote data. Once the NetCDF data are read, the plugin combines and formats the required variables (longitude, latitude, seismic velocity, and depth). These newly formatted values are then converted into the sph internal representation to be used as spherical harmonic data by ASPECT. The conversion and processing of data all takes place within the ASPECT program. Both plugins have been integrated to allow the user to lookup remote data in a seamless fashion and broaden the types of data that can be requested by the user.

Emmanuel Njinju

and 3 more

The EarthCube BALTO (Brokered Alignment of Long-Tail Observations) project is aimed at developing new cyberinfrastructures that enables brokered access to diverse geoscience datasets. Towards achieving this BALTO objective, we developed a plug-in for the community extensible NSF open-source code ASPECT (Advanced Solver for Problems in Earth’s Convection) that permits ASPECT to read data from the BALTO server (OPeNDAP’s Hyrax open-source data server) over the web. We present a use-case of the BALTO-ASPECT client, which accesses lithospheric structures from the BALTO server to constrain a 3-D lithospheric modulated convection (LMC) modeling and melt generation beneath the Rungwe Volcanic Province (RVP) and the Malawi Rift. We test the hypothesis that at least part of the melt feeding the RVP is generated from LMC. In the model, we assume a rigid lithosphere, while for the asthenosphere we use non-Newtonian, temperature-, pressure- and porosity-dependent creep laws of peridotite. We find that a significant percentage of decompression melt from LMC occurs at a maximum depth of ~200 km beneath the axis of the Malawi Rift, consistent with the location and maximum depth of imaged low velocity zones. At shallower depths (~100 km), the melting region is focused beneath the RVP where there is rapid (~3 cm/yr) upwelling. Our results suggest that asthenospheric upwelling due to LMC is the main source of melt beneath the RVP and might also entrain the plume head materials with reported high 3He/4He values. We, therefore, propose that part of the melt beneath the northern Malawi Rift feeding the RVP can be generated by LMC without necessitating plumes impinging the base of the lithosphere at present. This use-case demonstrates the capability of the BALTO-ASPECT client to accelerate research by brokering input data from the BALTO server for modeling LMC and melt generation.