stefanmertl.com/science

Greenland glacier monitoring – part 2 – why did we go there?

scientificSteve — Thu, 17 May 2012 17:40:55 +0000

In 2008, an Austrian team including Daniel and Gernot went to Zackenberg within the framework of the International Polar Year. They mainly did ground penetrating radar (GPR) measurements of the Freya glacier and the A.P. Olsen ice cap. You can read about their experiences during this trip in this blog (only in german).

The results of their studies revealed some very interesting englacial features (see figure 1) which are most likely related to the outburst of the glacier dammed lake Lake A.P.Olsen.

Figure 1: GPR crosssection. (source: ZAMG, Daniel Binder)

The Lake A.P. Olsen fills every year during summer and it empties sometime between autumn and spring. The Zackenberg GeoBasis research programme has installed a timelapse camera at the lake which takes an image every day. These photo sequences proof, that the lake empties very fast within one day (see figure 2).

Figure 2: The lake fills up during summer and it empties every year. The time when the lake empties is not fixed. It happens sometime between autumn and spring. (source: GeoBasis)

With this information we planned a seismic- and geodetic monitoring network to be deployed at the A.P.Olsen glacier. The network should be operating one year to catch the whole cycle of the filling and emptying of the lake. Moreover a dense GPR study is planned to further investigate the area of the glacier having the englacial features. Figure 3 shows the monitoring network which we installed at the A.P.Olsen glacier during our stay in 2011.

Figure 3: The Lake A.P.Olsen monitoring network consists of 5 seismic/gps stations (APO1 to 5) and one gps reference station (APO6) at the terminus of the glacier. (orthophoto source: GEUS)

In the next part of this series I’m going to give you some more details on the construction of the stations and how we set everything up at the Zackenberg base station.

Greenland glacier monitoring – part 1 – Travel to Zackenberg

scientificSteve — Fri, 04 May 2012 06:39:00 +0000

In April, I had the opportunity to join a research travel to Zackenberg/Greenland to deploy a seismic and geodetic monitoring network at the A.P.Olsen glacier. The first part of this trip was the travel to Zackenberg. With continuously shrinking airplanes and at the end a convoy of snow-scooters Daniel Binder, Gernot Weyss and me made it to the research station Zackenberg ZERO.

pSysmon – edit geometry

scientificSteve — Tue, 21 Feb 2012 20:49:36 +0000

I’m falling in love with Python more and more while encountering the beauty of this language and the trillions of already existing excellent code libraries. pSysmon is now doing it’s work using the multiprocessing module to provide real parallel computing. Moreover I’m using sqlAlchemy as the pSysmon database back-end. It enables the usage of various database engines and a much more efficient and readable code for database transactions. With these changes the basic framework for pSysmon is almost at the point where I want it to be.

As a teaser two screenshots of the geometry dialog follow. The geometry of the seismic networks is read from the database and XML files. The content of the inventory read from an XML file can be saved to the database. The assignment of stations and sensors is done by drag’n'drop. The geometry can be checked visually in a map and the sensor’s transfer functions will also be plotted.

tracedisplay development – stations and channels

scientificSteve — Mon, 31 Oct 2011 14:39:53 +0000

The development of pSysmon’s major visualization tool keeps on going. I already have added the support for channels and stations.
The next steps will be to add user interactivity and a dynamic integration of processing plugins.

tracedisplay development – first visualizations

scientificSteve — Sun, 23 Oct 2011 18:43:12 +0000

After a hard struggle with the correct resize behaviour of matplotlib canvases in wxPython panels I have finished the first step towards a pSysmon tracedisplay module. See the following screenshot for a quick stack of TdView panels. Each TdView holds an axes to display the data.

seismon breaking free

scientificSteve — Thu, 20 Oct 2011 12:34:57 +0000

After a positive evaluation of Python to replace Matlab and the discovery of the great work done by the obspy guys I have decided to free Seismon and translate it to the Python programming language. Seismon is becoming pSysmon.
Follow me here on my way towards a free seismological prototyping software.

Here’s a first glance at the pSysmon main window:

This summer

scientificSteve — Tue, 27 Sep 2011 21:35:43 +0000

EGU 2011

scientificSteve — Fri, 25 Mar 2011 18:21:53 +0000

In almost a week the European Geoscience Union General Assembly 2011 is going to start in Vienna. I’ll be there the whole week and it would be a good possibility to meet each other, have a short chat about Seismon and get a demonstration of the latest Seismon developments. I’m involved in several poster presentation and of course you can find me there during the presentation time.

Here’s a short overview of my schedule:

Monday, 4.Apr., (SM1.3, Attendance 17:30–19:00)

XY677 EGU2011-6264
Usage of SEISMON within the WEBNET seismic network
Jan Michálek, Jana Doubravová, and Stefan Mertl

XY670 EGU2011-6950
Location performance of the ALPAACT seismic network
Maria-Theresia Apoloner, Ewald Brückl, Johanna Brückl, Walter Loderer, Stefan Mertl, and Bernd Schurr

Tuesday, 5.Apr., (NH3.4, Attendance 17:30–19:00)

XY551 EGU2011-2399
Seismic- and GBSAR monitoring of a rock-slide
Stefan Mertl, Sabine Rödelsperger, and Stefan Weginger

Thursday, 7. Apr., (NH3.8, Attendance 17:30–19:00)

XY380 EGU2011-3412
The Gradenbach Observatory – monitoring in-stationary deep-seated gravitational creep by geodetic, hydrological, and seismological methods
Ewald Brueckl, Fritz K. Brunner, Erich Lang, Stefan Mertl, Martin Mueller, and Ulrike Stary

Looking forward to meeting you,
Stefan.

Developer’s Guide

scientificSteve — Thu, 24 Mar 2011 23:16:51 +0000

I have updated the documentation and added the Developer’s Guide. The Developer’s Guide will help you to add your own code to Seismon.
The currently available chapters in the Developer’s Guide explains how to create tracedisplay tools and gives some examples for the most common tool types.

Go and read the Developer’s Guide to make Seismon do your things.

feel – see – hear

scientificSteve — Thu, 10 Mar 2011 18:34:24 +0000

I one of my favorite book stores I stumbled over the small picture book Seismic Stations by Florian Dombois. The book shows a collection of pictures of seismic stations of the GSN network which have been collected from the Iris homepage.

Searching for more work by Florian, I stumbled over his site www.auditory-seismology.org and I got really excited. Auditory-seismology gives some examples of seismograms turned into sound by compressing the time and resampling. Listening to those lines that I daily work with makes a lot of fun. Browsing through the website and reading some of his articles I got inspired to audify the seismograms by myself. Unfortunately I can’t use the Sonifyer tool (which I’d love to try) cause I’m not working on a Mac, so I started to write my own audification tool in Seismon.

I have coded the audification tool to listen to the seismograms displayed in the Seismon tracedisplay window and I can’t stop using this tool. It’s unbelievable what’s going on inside the earth and hearing all those different types of signals recorded by a geophone is stunning! I already found the most scary sounding seismic station in the world, but more on that later.

For now I have created a small example of an earthquake audified using Seismon. I’ve used the ML 4.2 earthquake in Hungary that already has been the topic of my ODC video tutorial.

Take a look at my first SeismoSounds example and listen how the earthquake sound changes with epidistance.