Simon C. Stähler
I'm a postdoctoral seismologist mainly interested in all the inverse problems our discipline poses: Finding out about Earth's history contained in the mantle, about the sources of earthquakes and what that tells us about the tectonic situation of places.
Part of my interest is the epistemological question to find out how much we actually can find out given the observations we have. Since Earth science tries to infer the billion year history of the whole earth just from some scrambled observations at the very surface of the planet, which all happen to happen now, that's a rather curious task.
and why you should be interested
Fully probabilistic seismic source inversion – Part 2: Modelling errors and station covariances
The long-awaited sequel
How can we construct a Likelihood function for non-Gaussian noise on seismic waveforms? Turns out that the dependable Correlation Coefficient follows a log-normal distribution, so we can use that.
Stähler, S. C., K. Sigloch, Fully probabilistic seismic source inversion – Part 2: Modelling errors and station covariances, in public review for Solid Earth
Performance report of the RHUM-RUM ocean bottom seismometer network around La Réunion, western Indian Ocean
Overview of OBS performance in the RHUM-RUM project, especially in comparison between the German (DEPAS) and the French (INSU) seismometers.
Stähler, S. C., Sigloch, K., Hosseini, K.,
Crawford, W. C., Barruol, G., Schmidt-Aursch, M. C., Tsekhmistrenko, M.,
Scholz, J.-R., Mazzullo, A., and Deen, M.: Performance report of the
RHUM-RUM ocean bottom seismometer network around La Réunion, western
Indian Ocean, Adv. Geosci., 41, 43-63, doi:10.5194/adgeo-41-43-2016,
The Lack of Equipartitioning in Global Body Wave Coda
Analysing seismograms of the deep Okhotsk earthquake, we can show that the late coda is dominated by waves traveling in great-circle direction. The coda is not equipartioned and cannot be easily used for correlation analysis.
Sens-Schönfelder, C., R. Snieder, and S. C. Stähler (2015), The Lack of Equipartitioning in Global Body Wave Coda, Geophys. Res. Lett., 42,
Fully probabilistic seismic source inversion I - Efficient parametrization
This paper deals with the inverse problem of seismic point source inversion. It describes an efficient parametrization to invert for earthquake depth, moment tensor and source time function using Bayesian inference with Malcolm Sambridge's Neighbourhood Algorithm.
Stähler, S. C. and K. Sigloch (2014): Fully probabilistic seismic source inversion – Part 1: Efficient parametrisation, Solid Earth, 5, 1055-1069
Instaseis: instant global seismograms based on a broadband waveform database
Instaseis is a Python library to calculate broadband seismograms for arbitrary source-receiver configurations, including finite faults and single forces from a stored AxiSEM wavefield.
van Driel, M., Krischer, L., Stähler, S. C., Hosseini, K., and Nissen-Meyer, T. (2015). Instaseis: instant global seismograms based on a broadband waveform database
Solid Earth, 6, 701-717
AxiSEM: broadband 3-D seismic wavefields in axisymmetric media
This is a release paper for the axially-symmetric spectral element solver AxiSEM. Use it to generate global seismograms for up to 1 Hz.
Nissen-Meyer, T., M. van Driel, S. C. Stähler, K. Hosseini, S. Hempel, L. Auer, A. Colombi, and A. Fournier (2014): AxiSEM: broadband 3-D seismic wavefields in axisymmetric media, Solid Earth, 5, 425-445,
Triplicated P-wave measurements for waveform tomography of the mantle transition zone
P-waves from distances between 1000 and 3000 km contain a lot of information about the upper mantle and the transition zone. We show a way to use them for finite-frequency tomography.
Stähler, S. C., K. Sigloch, and T. Nissen-Meyer (2012), Triplicated P-wave measurements for waveform tomography of the mantle transition zone, Solid Earth, 3(2), 339-354,
Monitoring stress changes in a concrete bridge with coda wave interferometry
Coda waves contain information about a large volume around the source and receiver. We use that method to monitor stress changes in a bridge during construction.
Stähler, S. C., E. Niederleithinger, and C. Sens-Schönfelder (2011), Monitoring stress changes in a concrete bridge with coda wave interferometry, Journal of the Acoustical Society of America, 129(4), 1945-1952,
The latest from the lab and the field
Introductory seismology with animations
Seismic wavefield perturbed by plumes and slabs
This video shows the seismic wavefield of an earthquake in a mantle that contains a subducting slab on the left and an upwelling megaswell-structure on the right. The situation is comparable to Southern America on the left and Africa on the right with the earthquake happening in the Central Atlantic ocean at the mid-ocean ridge.
Note that the velocity anomalies are exaggerated to make the effect more prominent.
Seismic wavefield in the Jovian moon Europa
AxiSEM is able to model seismic wave propagation in terrestrial planets in general. One of the most fascinating objects in the solar system is Europa, with its abysmal ocean below a few kilometers of ice. The structure results in a wavefield that is completely different from what we see on Earth. Most of the wave energy is either contained inside the ice (especially SH-waves) or is reverberating inside the ocean.
Seismic wavefield in the Earth
This video shows the seismic wavefield in the Earth's mantle assuming the velocity depends only on depth.
Seismic wavefield perturbed by a megaswell-structure
This video shows a wavefield in a mantle that contains a megaswell.
standing next to giants (without stepping on their toes)
University of Oxford
University of Hamburg
Earthquake-free seismology. Using seismic signals created from ocean waves, trucks or just anything for monitoring.
Jet Propulsion Laboratory