Geophysics

Borehole NMR – an MRI for Earth’s subsurface

Video

source: Borehole Nuclear Magnetic Resonance (NMR): a valuable tool for environmental site management, doi:10.5066/F73J3BW0, USGS

Python wrappers for the Generic Mapping Tools on the way

Standard

An interface for interoperability between the Generic Mapping Tools (GMT), a tool used by geophysicists to create research-quality figures, and Matlab has recently been developed that allows GMT users to interact with Matlab and Matlab users to make use of GMT.

GMT wrappers are currently also being developed for the Python programming language, particularly to be used in the IPython/Jupyter notebook due to an initiative by Leonardo Uieda (and his professor Paul Wessel) whose Postdoc is being funded by the NSF. You can watch his talk at the SciPy 2017 conference below.

Some of the mentioned advantages to which I attest  include:

  • Begin and End statements are introduced to eliminate the need to pipe postscript results into a file in each line of code being written. This also eliminates the need to use the -K and -O flags which keep the file open and updates it, respectively. The -K and -O flags are a major confusion for newcomers to GMT.
  • temporary files are created under the /tmp directory, in Linux, so they will automatically be cleaned once the jupyter notebook is closed or the operating system is rebooted. Moreover, every project will have its own  directory so files from different projects don’t get mixed up.
  • GMT documentation straight in the Jupyter notebook
  • Matplotlib- & Basemap-like behaviour, particularly inline viewing of figures, using gmt.show()
  • Pythonic aliases make the compact GMT flags

To contribute: github.com/GenericMappingTools

Reference

Cook, T. (2017), A powerful new tool for research, Eos, 98, https://doi.org/10.1029/2017EO077489. Published on 17 July 2017.

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Converting Greenhouse Gases to Rocks

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One of the ways scientists are attempting to reduce greenhouse gases is to inject these gases into the ground. Specifically, they are testing injecting them, into basalt which is type of igneous rocks usually forming the first (rock) layer (sandwiched between the sedimentary & gabbro layers) in the oceanic crust basalt and in volcanic regions.

The above video features Iceland and its geothermal plants. Iceland is a heaven for geothermal energy as it lies along the Mid-Atlantic Ridge (MAR) (i.e. where Mid-Atlantic ocean floor is spreading apart in opposite directions forming a ridge). Most notably Iceland lies along the V-Shaped Reykjavik ridge (figure below; Google maps) which is part of the Norther MAR.

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Animation of the Italy Earthquake’s Seismic Velocity

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A “real-time” animation of the seismic (vertical) velocity of Italy’s 5.5 Mw earthquake that hit between the Aquila and Rieti provinces. The second half of the animation shows the whole country and surrounding area.

Real-time indicates that the video reflects how the waves propagated in real-time. It’s neither slowed down not sped up.

Red color indicates relatively higher vertical velocities indicating the ground is moving upwards while the blue color indicates the lower (negative) velocities indicated a downward movement of the ground. Color intensity refers to the magnitude.

Fluid Mechanics video lectures

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In a previous post we selected some resources on fluid dynamics. In that post we suggested the videos from the National Committe for Fluid Mechanics (notes on the website) that date to the 1960’s and is an excellent exposition to fluid mechanics. We share them below following a very clear demonstration of Euler’s equation and Bernoulli’s integral:

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