Before you Start:
Please look through Lectures 12, 13, and 14 before you get started with this lab. Lectures 12 and 13 will remind you of the concepts and processing work flows of InSAR, while Lecture 14 covers the use of InSAR data in geophysical modeling. For further reading on the use of InSAR in volcano source modeling, please consult the “Volcano Source Modeling” section in the Further Reading component of this website.
Like the previous lab, this exercise is done within UAF’s cloud-based Open SAR Lab, which is accessible to you at opensarlab.asf.alaska.edu. The lab is implemented within the Amazon Web Services (AWS) cloud and uses Jupyter Notebooks as instructional method.
A 2019 live recording of this lab can be found here.
Accessing the Open SAR Lab and Completing the Lab Exercise
To access and complete the Open SAR Lab exercise, please follow these steps:
- Access the Open SAR Lab at opensarlab.asf.alaska.edu
- Log in with your username and password (contact me should you need login credentials).
- Start the Juypter Notebook (GEOS 657-Lab6-VolcanoSourceModelingfromInSAR.ipynb). A screenshot of the Notebook opened in your Jupyter console is shown to the right.
- Complete the notebook and the lab assignments.
- Submit your assignments as instructed in the notebook.
Goals of this Lab:
This labs will introduce you to the intersection between Radar Remote Sensing and Inverse Modeling. Specifically, you will learn how to use InSAR observations to determine the most likely parameters of a volcanic magma source underneath Okmok volcano, Alaska. Okmok is one of the more active volcanoes in Alaska’s Aleutian Chain that had its last (known) eruption in summer of 2008. Okmok is interesting from an InSAR perspective as it inflates and deflates heavily as magma moves around in its magmatic source located roughly 2.5 km underneath the surface. To learn more about Okmok volcano and its eruptive history, please visit the very informative site of the Alaska Volcano Observatory.
We will use a pair of C-band ERS-2 SAR images acquired on Aug 18, 2000 and Jul 19, 2002 to analyze the properties of a volcanic source that was responsible for an inflation of Okmok volcano of more than 3cm near its summit. We will assume that the source can be modeled as an inflating point source (a so-called Mogi source; see Lecture 14) and will use a grid-search method for finding the source model parameters (3D source location and volume of magma influx) that best describe our InSAR-observed surface deformation. The lab involves reading, running, and writing some Matlab scripts. All necessary data and Matlab scripts are available in the download section below.