Seismic observations with broadband instruments at Santorini volcano


Published: Jan 1, 2007
Keywords:
Santorini volcanic earthquakes spectral analysis
A. Kolaitis
P. Papadimiriou
I. Kassaras
K. Makropoulos
Abstract

Two arrays equipped with broadband sensors were installed for a period of 10 months, in order to study the seismic activity in the area of Santorini (Thira) volcano. During these periods, about 330 earthquakes were recorded and located within a radius of 50 km from the center of the caldera. An iterative damped traveltime inversion procedure yielded a local 1-D Ρ-wave velocity model and improved locations with an accuracy better than 5 Km in both horizontal and vertical components for 135 earthquakes. Those are mainly distributed within a depth range 5-18 Km, in the vicinity of the submarine Kolumbo Reef (NE of Santorini Island). Signal analysis of the recorded volcanic earthquakes including typical Fourier transformations and several operations in the time-frequency domain, allowed their dominant frequency determination and their classification into three groups based on waveform appearance and frequency content: (1) highfrequency events; (2) low-frequency events; and (3) volcanic tremor. Frequencytime analysis of tremor, detected at three stations, revealed two kinds of harmonic tremor with one sharp peak, at 3-5 Hz and 8.5-10 Hz.

Article Details
  • Section
  • Geophysics and Seismology
Downloads
Download data is not yet available.
References
Budetta, G., Condarelli, D., Fytikas, M., Pascale, G., Pinna, E., and Rapolla, Α., 1983. Prospezioni Giofisiche nelle isole di Santorini, Grecia. Rep. Inst. Geol. Miner. Explor., Athens, l-38pp.
Chouet, B.A., 1985. Excitation of a buried magmatic pipe: A seismic source model for volcanic tremor, J. Geophys. Res., 90, 1881-1893.
Chouet, B.A., 1986. Dynamics for a fluid-driven crack in three dimensions by the finite difference method, J. Geophys. Res., 91, 967-992.
Chouet, B.A., 1988. Resonance of a fluid driven crack: radiation properties and implications for the source of long-period events and harmonic tremor, J. Geophys. Res., 93, 4375-4400.
Chouet, B.A., 1996a. Long-period volcano seismicity: its source and use in eruption forecasting, Nature, 380, 309-316.
Chouet, B.A., and Julian, B.R., 1985. Dynamic of an expanding fluid-filled crack, J. Geophys. Res., 90, 11187-11198.
Crosson, R.S., 1976. Crustal structure modeling of earthquake data; 1, Simultaneous least squares estimation of hypocenter and velocity parameters, J. Geophys. Res., 81, 3036-3046.
Delibassis, N., Chailas, S., Lagios, E., and Drakopoulos, J., 1989. Surveillance of Thera Volcano (Greece): Microseismological Monitoring, 3rd International Congress 'Thera and the Aegean World'. Santorini, 3-8 September 1989, vol. II, 199-206pp.
Delibassis, N., Sachpazi, M., Chailas, S., and Karantonis, G., 1993. Microearthquake activity of the Santorini Volcanic island during the period 1985-1989, Ann. Geol. de Pay Hellénique, 36, 181-207.
Dimitriadis, I.M., Panagiotopoulos, D.G., Papazachos, P.M., and Hatzidimitriou, E.E., Karagianni and Kane I, 2005. Recent seismic activity (1994-2002) of the Santorini volcano using data from local seismological network. The South Aegean Active Volcanic Arc. In M. Fytikas and G.E. Vougioukalakis (eds), Developments in Volcanology, vol.7. Elsevier B.V.
Druitt, T.H., Mellors, R.A., Pyle, D.M., and Sparks, R.S.J., 1989. Explosive mechanism on Santorini, Greece, Geophysical Magazine, 126, 95-126.
Druitt, T.H., Davies, M.S., Edwards, .L., Sparks, R.S.J., Mellors, R.M., Pyle, D.M., Lanphere, M., and Barreirio, B., 1999. The Santorini volcano, Geological Society Special Memoir, 19 Geological Society Pub House, London.
Dziak, R.P., and Fox, C.G., 2002. Evidence of harmonic tremor from a submarine volcano detected across the Pacific Ocean basin. J. Geophys. Res., 107 (B5), doi: 10.1029/2001JB000177.
Fytikas, M., Kolios, N., and Vougioukalakis, G., 1990. Post-Minoan Volcanic Activity of the Santorini Volcano. Volcanic hazard and risk, forecasting possibilities. In D.A. Hardy (ed.), Thera and the Aegean World III, 2. The Thera Foundation, London, 183-198pp.
Goldstein, P., Dodge, D., Firpo, M., and Ruppert, S., 1998. What's new in SAC2000? Enhanced processing and database access, Seismol. Res. Lett., 69, 202-205.
Goldstein, P., and Minner, L., 1996. SAC2000: seismic signal processing and analysis tools for the 21st century, Seismol. Res. Lett., 67, 39.
Hurst, A.W., 1992. Stochastic simulation of volcanic tremor from Ruapehu, J. Volcanol. Geotherm. Res., 51, 185-198.
Jousset, P., Neuberg, J., and Sturton, S., 2003. Modelling the time-dependent frequency content of the low-frequency volcanic earthquakes, J. Volcanol. Geotherm. Res., 128, 201-223.
Karagianni, E.E., Panagiotopoulos, D.G., Panza, G.F., Suhadolc, P., Papazachos, C.B., Papazachos, B.C., Kiratzi, Α., Hatzfeld, D., Makropoulos, K., Priestley, K., and Vuan, Α., 2002. Rayleigh wave group velocity tomography in the Aegean area, Tectonophysics, 358,187-209.
Kassaras, I., 2002. Upper mantle structure of the Aegean region derived from the dispersion of seismic surface waves, PhD Thesis, University of Athens, Greece.
Kawakatsu, H., Kaneshima, S., Matsubayashi, H., Ohminato, T., Sudo, Y., Tsutsui, T., Uhira, Κ., Yamasato, Η., and Legrand, D., 2000. Aso94: Aso seismic observation with broandband instruments, J. Volcanol. Geotherm. Res., 101, 129-154.
Kissling, E., Ellsworth, W.L., Eberhart-Phillips, D. & Kradofler, D., 1994. Initial reference models in local earthquake tomography, J. Geoph. Res., 99, 19635-19646.
Kissling, E., Solarino, S., and Cattaneo, M., 1995. Improved seismic velocity reference model from local earthquake data in Northwestern Italy, Terra Nova, 7, 528-534.
Konstantinou, I., and Schlidwein, V., 2002. Nature, wavefield properties and source mechanism of volcanic tremor: a review, J. Volcanol. Geotherm. Res., 119, 161-187.
Latter, J., 1979. Volcanological observations at Tongarino national park. 2: Types and classification of volcanic earthquakes 1976-1978, Geophysics Division Report 150, Dept. Sei. Ind. Res.
Lee, W.H., and Lahr, J.E., 1975. HYP071 a computer program for determining hypocenter magnitude and first motion pattern of local earthquakes, Geol. Survey Open-File Report, USA, 75-311.
Leet, R.C., 1988. Saturated and subcooled hydrothermal boiling in groundwater flow channels as a source of harmonic tremor, J. Geophys. Res., 93, 4835-4849.
McNutt, S.R., 1986. Observations and analysis of B-type earthquakes, explosions and volcanic tremor. At Pavlof Volcano, Alaska. Bull. Seismol. Soc. Am., 76, 153-175.
McNutt, S.R., 1996. Seismic monitoring and eruption forecasting of volcanoes: A review of the state-of-the-art and case histories. In Scarpa, Tilling (eds.), Monitoring and Mitigation of Volcanic Hazards, Springer, Berlin, 100-146pp.
McNutt, S.R., (2000). Volcanic seismicity. In: Sigurdsson H. (Ed.), Encyclopedia of volcanoes, Academic Press San Diego, 1015-1033.
Makropoulos, K., Kouskouna, V., Karnassopoulou, Α., Dando, P., and Varnavas, S.P., 1998. Seismicity in the Aegean hydrothermal system in relation to biogeochemical parameters, submitted to J. Physics and Chemistry of the Earth.
Mascle, J., and Martin, L., 1990. Shallow structure and recent evolution of the Aegean sea: A synthesis based on continuous reflection profiles, Mar. Geol., 94, 271-299.
McKenzie, D.P., 1978. Active tectonics of the Alpine Himalayan Belt: The Aegean Sea and surrounding regions, Geophys. J.R. Astron. Soc, 55, 217-254.
Minakami, T., 1960. Fundamental research for predicting volcanic eruptions (Part 1), Bull. Earthq. Res. Inst. Univ. Tokyo, 38, 497-544.
Minakami, T., 1974. Seismology of volcanoes in Japan. In Civetta et al. (eds) Physical Volcanology Developments in Solid Earth Geophysics vol 6. Elsevier Amsterdam l-27pp.
Neuberg, J., Luckett, R., Baptie, B., and Olsen, K., 2000. Models of tremor and low-frequency earthquake swarms on Montserrat, J. Volcanol. Geotherm. Res., 101, 83-104.
Papanikolaou, D., Lekkas, E., Syskakis, D., and Adamopoulou, E., 1993, Correlation on neotectonic structures with the geodynamic activity in Milos during the earthquakes of March 1992, Bull. Geol. Soc. Greece, XXVIII/3,413-428.
Papazachos, B.C., 1989. Long and short term prediction of the volcanic eruption in Santorini. In Proceedings of 3rd International Congress 'Thera and the Aegean World III", Volume 2, September 4-8 1989, Santorini, Greece, 125-129pp.
Papazachos, B.C., Kiratzi, A.A., and Papadimitriou, E.E., 1991. Regional focal mechanisms for earthquakes in the Aegean area, Pure Appi. Geophys. 136,405-420.
Papazachos, B.C., Mountrakis, D.M., Papazachos, C.B., Tranos, M.D., Karakaisis, G.F., and Savaidis, A.S., 2001. The fault which has caused the known major earthquakes in Greece and sourrounding region between the 5th century BC and today. Proceedings of 2nd National Conference Anti-Seismic Engineering and Technical Seismology, November 28-30, 2001, Thessaloniki, Greece, 17-26pp.
Papazachos, B.C., and Panagiotopoulos, D., G., 1993. Normal faults associated with volcanic activity and deep rupture zones in the southern Aegean volcanic arc, Tectonophysics, 220, 301-308.
Pavlides, S.B., and Valcaniotis, S., 2003. Tectonic regime of Santorini-Amorgos area, Proceedings of International Conference "The South Aegean Active Volcanic Arc: Present Knowledge and Future Perspectives ", September 17-20 2003, Milos Island, Greece. Book of abstracts, 76p.
Perissoratis, C, 1996. The Santorini volcanic complex and its relation to the stratigraphy and structure of the Aegean arc, Greee, Marine Geology, 128, 37-58.
Schlidwein, V., Wasserman, J., and Scherbaum, F., 1995. Spectral analysis of harmonic tremor signals from Mt. Semeru, Indonesia, Geophys. Res. Lett., 22, 1685-1688.
Seidl, D., Schick, R., and Riuscetti, M., 1981. Volcanic tremors at Etna: A model for hydraulic origin, J. Volcanol. Geotherm. Res., 44, 43-56.
Seidl, D., Kirbani, S.B., and Brustle, W., 1990. Maximum entropy spectral analysis of volcanic tremor using data from Etna (Sicily) and Merapi (central Java), Bull. Volcanol., 52, 460-474.
Sherburn, S., Scott, B.J., Nishi, Y., and Suguhara, M., 1998. Seismicity at White Island volcano, New Zealand: a revised classification and inferences about source mechanism, J. Volcanol. Geotherm. Res., 83, 287-312.
Shirokova, E., 1972. Stress pattern and probable motion in the earthquake foci of the Asia Mediterranean seismic belt. In L.M. Balakina et al. (eds), Elastic Strain Field of the Earth and Mechanisms of Earthquake Sources, Nauka, Moscow, p.8.
Talandier, J., and Okal, E.A., 1996. Monochromatic Τ waves from underwater in the Pacific Ocean: ringing witnesses to geyser processes? Bulletin of the Seismological Society of America, 86 (5), ringing 1529-1544.
Most read articles by the same author(s)