Hello Planetary Pals,
This week’s blog post will be a thesis update. After the last group meeting two weeks ago, I followed Ashka’s advice in completing the ungraded pre-proposal. This will serve as a skeleton upon which I will build for the thesis proposal. The Geology Grad Seminar has set the thesis proposal to be due on Monday.
The thesis proposal is my current focus and takes precedence over the other tasks I have on schedule. The format follows up on that of the pre-proposal. I will need to create a title page and bibliography, as well as write seven pages of text. I have done very little of processing, and as such, most of the figures and tables in the report will not be of my own. That being said, I will be able to include some of the processed Sentinel-1 images that I created in SNAP. There will be a general introduction to the topic. This will end with my thesis statement which explains exactly what I will be examining and why it is important. Then I will add a section on the previous works about radar, lava fields, and Holuhraun in particular. I will include a sections on methodology. This includes writing about how Sentinel-1 images and GPR radargrams are acquired, processed, and examined.
My title has been chosen and will tentatively be called “Mapping the Evolution of the Exposed and Buried Lava Flows at Holuhraun, Iceland. “The event was able to be viewed in real-time, allowing scientists to view it’s emplacement as it happened. There were three distinct phases. First, the lava was moved through channels. The second flow regime occurred due to ponding of the lava as it abutted on a topographic feature. The final stage of emplacement was the formation of lava tubes, where the molten rock was emplaced mainly below the surface. This describes the volcanic evolution of the site. My research, however, will focus on a different geologic evolution that is occurring at the site, by characterizing how the surface roughness has changed since emplacement. I will examine how erosion and burial affects the polarity in the radar images and will study how well GPR can image below the eolian deposits overlying the field.
As for the methodology, I have already begun the first steps in processing the data. I have acquired several Sentinel-1 radar images from VERTEX. These are high resolution dual-pol images taken in the summer months. Yesterday afternoon I was able to meet with Jahnavi to go over processing in SNAP. This is important because the original TIFFs are somewhat unprocessed, uncalibrated, and noisy. At the moment, however things are kind off rough; I am sharing a computer with Jahnavi, so we will need to work out a schedule of who can use it when. As well, the computers do not have ArcGIS, so after processing the data in SNAP, I can’t view them right away, but must view them on my home desktop. This worries me because I could spend an entire day processing but won’t be able to know for sure that I haven’t messed anything up until much later. The other part to my methodology section will explain how the GPR will be used. I will process this data in the newly acquired ekko-view software.
My objectives are four-fold: (1) to use Sentinel radar data to characterize the three different flow regimes identified by (Pederson et al., 2017) at Holuhraun. (2) Observe the evolution of the surface roughness of the Holuhraun lava field using orbital radar images, with emphasis on how it has been eroded and buried over time. (3) Use GPR to identify the depth and volume of the sand that has buried the lava field. (4) Compare and contrast Holuhraun with extraterrestrial basaltic lava fields on Mars.
This research is important for a number of reasons. The recency of the Holuhraun eruption event allows for characterization of the event in the early stages; older lava fields in Iceland can be hundreds to thousands of years old. Since the lava field was observed as it was erupting, much more is already known about its emplacement style. A number of lava fields in Iceland are already described as being good analogs to extraterrestrial lava fields, especially those on Mars. By studying this new lava field using radar imaging and GPR (common remote sensing techniques in planetary science), my research will prove to be exciting since it will determine how good of an analog Holuhraun is to similar Martian features.