Dr. Céline Hadziioannou
Junior Professor in Seismology, University of Hamburg
former Emmy Noether Fellow, project title:
"The origin of Love waves in the ocean generated noise wave field"
University of Hamburg
Institute of Geophysics
20146 Hamburg -- Germany
email: celine.hadziioannou [at] uni-hamburg.de
Tel. +49 (0)40 42838 2980
Noise correlations have revolutionized seismology. They make it possible to exploit the vast amounts of background noise recorded continuously around the world. In a way, they allow us to exploit seismic noise to perform earthquake-free seismology. The resulting explosion of high-resolution tomographic images in the past decade provides us with better event locations, better strong motion predictions and a deeper understanding of crustal dynamics. All of these have important implications for natural hazard management.
Noise correlations have also been used successfully to monitor wave speed changes over time in potentially dangerous structures such as landslides, volcanoes and active fault zones. Most of the applications so far have concentrated on the vertical component records, but recently more interest arises to include the information contained in the horizontal components.
However, as the methods employed are developed and become more accurate, their drawbacks are becoming more apparent. One of the problems in noise correlation, is that the resulting "Green's function" does not only carry the wanted information about the propagation medium, but also about the noise sources. Therefore, to improve the noise correlation technique, it is important to have a good understanding of the noise sources and their behavior. The sources of the vertical component motion in microseismic Rayleigh waves are already widely studied, while those for the horizontal shear motions in Love waves remain relatively unexplored. My research aims at characterizing and understanding Love waves in ambient seismic noise, and their contribution to noise correlation methods. Several fundamental questions are addressed:
How are microseismic Love waves generated?
Where are Love waves generated? What are the geographic differences compared to Rayleigh wave generation areas?
How much energy do Love waves contribute to seismic noise? How does this depend on the frequency?
When are the strongest Love waves generated? Does their frequency content change over time?
Rotational Seismology Event Database
Online access to more than 17,000 Earthquake waveforms and processed plots from signals recorded simultaneously by the Wettzell ring laser and a nearby seismometer.
C. Juretzek, C. Hadziioannou, Linking source region and ocean wave parameters with the observed primary microseismic noise, submitted to Geophys. J. Int.
S. Donner, C.-J. Lin, C. Hadziioannou, A. Gebauer, F. Vernon, D. C. Agnew, H. Igel, U. Schreiber, J. Wassermann, Comparing direct observation of strain, rotation, and translation with array estimates at Pinon Flat Observatory, California, in review at Bull. Seism. Soc. Am.
J. Salvermoser, C. Hadziioannou, S. Hable, L. Krischer, B. Chow, C. Ramos, J. Wassermann, U. Schreiber, A. Gebauer, H. Igel, An event database for rotational seismology, Seismological Research Letters 88, Mar. (2017)
T. Tanimoto, C.-J. Lin, C. Hadziioannou, H. Igel, and F. Vernon, Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by a small array at Piñon Flat observatory, California, Geophys. Res. Lett., 43, (2016)
C. Juretzek, C. Hadziioannou, Where do ocean microseisms come from? A study of Love-to-Rayleigh wave ratios, J. Geophys. Res. Solid Earth 121, 6741-6756 (2016)
A. Obermann, T. Planès, C. Hadziioannou, M. Campillo, Lapse-time dependent coda wave depth sensitivity to local velocity perturbations in 3-D heterogeneous elastic media, Geophys. J. Int. 207(1), 59-66 (2016)
C. Wu, A. Delorey, F. Brenguier, C. Hadziioannou, E. Daub, P. Johnson, Constraining depth range of S-wave velocity decrease after large earthquakes near Parkfield, California, Geophys. Res. Lett. 43, 6129-6136 (2016)
T. Tanimoto, C. Hadziioannou, H. Igel, J. Wassermann, U. Schreiber, A. Gebauer, B. Chow, Seasonal variations in the Rayleigh-to-Love wave ratio in the secondary microseism from co-located ring laser and seismograph, J. Geophys. Res. Solid Earth, 121, (2016)
J. Wassermann, A. Wietek, C. Hadziioannou, H. Igel,
Towards a Single Station Approach for Microzonation: Using Vertical Rotation Rate to Estimate Love-Wave Dispersion Curves and Direction Finding, BSSA, May (2016)
J. Salvermoser, C. Hadziioannou, S. Stähler, Structural monitoring of a highway bridge using passive noise recordings from street traffic - J. of the Acoust. Soc. Am. 138, 3864, (2015)
T. Tanimoto, C. Hadziioannou, H. Igel, J. Wasserman, U. Schreiber, A. Gebauer, Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by co-located ring laser and seismograph - Geophys. Res. Lett., 42 (2015)
doi: 10.1002/2015GL063637 [pdf]
- C. Hadziioannou, P. Gaebler, U. Schreiber, J. Wassermann, H. Igel - Examining ambient noise using co-located measurements of rotational and translational motion - Journal of Seismology: Special issue on rotational motions 16(4), 787-796 (2012)
doi: 10.1007/s10950-012-9288-5 [pdf]
- C. Hadziioannou, E. Larose, A. Baig, P. Roux, M. Campillo - Improving Temporal resolution in ambient noise monitoring of seismic wave speed - J. Geophys. Res. 116, B07304 (2011)
doi: 10.1029/2011JB008200 [pdf]
- R. Weaver, C. Hadziioannou, E. Larose, M. Campillo - On the precision of noise correlation interferometry - Geophys. J. Int. 185(3), 1384 - 1392 (2011);
doi: 10.1111/j.1365-246X.2011.05015.x [pdf] [bibtex] [arxiv]
- C. Hadziioannou, E. Larose, O. Coutant, P. Roux, M. Campillo - Stability of monitoring weak changes in multiply scattering media with ambient noise correlation: Laboratory experiments - J. Acoust. Soc. Am. 125(6), 3688-95 (2009)
doi: 10.1121/1.3125345 [appendix] [bibtex] [pdf]
- F. Brenguier, M. Campillo, C. Hadziioannou, N. M. Shapiro, R. M. Nadeau, E. Larose - Postseismic relaxation along the San Andreas Fault at Parkfield from continuous seismological observations, Science 321, 1478 (2008)
doi: 10.1126/science.1160943 [bibtex] [pdf]
(BSc, 6. Semester, 2017)
4th IWGoRS Meeting on rotational seismology in Tutzing, Germany
20-23 June, 2016
AMÜSE PhD conference, Hinterriss, Austria
10-12 June, 2016
Hum workshop at the Center for Advanced Studies in Munich (CAS)
September 12, 2014
4th Quest workshop in Benodet, France
May 19-25, 2013
Neustadt workshop on "Noise and Diffuse Wavefields"
11-14 November 2012
- AGU 2011: C. Hadziioannou, E. Larose, P.Roux, M. Campillo, J. Wassermann, H. Igel - Do variations of the ambient noise wavefield reflect on measured seismic velocity changes? [pdf]
- QUEST Workshop 2011: C. Hadziioannou, P. Gaebler, U. Schreiber, J. Wassermann, H. Igel - Examining ambient noise using co-located measurements of rotational and translational motion, Iceland, July 2011
- EGU 2011: C. Hadziioannou, E. Larose, Y. Aoki, T. Takeda, M. Campillo - Ambient seismic noise monitoring in Chuetsu, Japan and the area affected by wave speed variations [poster]
- QUEST Workshop 2010: C. Hadziioannou, F. Brenguier, E. Larose, M. Campillo - Introduction to Monitoring velocity variations using Ambient Noise Correlation: Application to Tiltmeter data [presentation], Sardinia, September 2010
- AGU 2009: C. Hadziioannou, E. Larose, A. Baig, M. Campillo - Increasing the temporal resolution of ambient seismic noise monitoring [poster]
- Workshop on Noise and Diffuse Wavefields, Neustadt, July 2009: C. Hadziioannou, E. Larose, O. Coutant, P. Roux, M. Campillo - Stability of Monitoring Weak Changes in Multiply Scattering Media with Ambient Noise Correlation: Laboratory Experiments. [extended abstract]
- AGU 2008: C. Hadziioannou, E. Larose, M. Campillo, P. Roux - Monitoring Weak Changes in Multiply Scattering Media with Coda Waves: Laboratory Experiments [poster]
- Joint Japanese/French workshop, Tokyo, June 2008: C. Hadziioannou - Postseismic relaxation along the San Andreas fault at Parkfield investigated with continuous seismological observations