Tehostekuvassa fysiikan laitosta etuoven suunnalta

8. Ultrasonic research

Participating scientists

  • L.J. Pesonen, prof. (emeritus)
  • E. Haeggström, Ph.D.
  • I. Lassila, Ph.Lic.
  • R. Karlqvist, M.Sc.

Project goals

We have, together with physics group, developed a novel ultrasonic device which allows the seismic Vp- and Vs-velocities to be determined under crustal pressures. The study reveals the significance of microcracks in causing the low velocity zones.

Highlights

Pressure closes pores leading to distinct increase of seismic velocity.
Fig.1. Pressure closes pores leading to distinct increase of seismic velocity.
Fig.2: Ultrasonic VpVs-meter
Fig.2: Ultrasonic VpVs-meter.
Borehole data from Chesapeake Borehole data from Chicxulub

Recent publications

  • Kohout, T., Karlqvist, R., Lassila, I.J., Eskelinen, J. J., Hortling , A., Pesonen, L., Haeggström, E., 2013. Ultrasonic Determination of Porosity in Homogeneous Ceramic Samples. Geophysica, 49(1-2), 25-32.
  • Elbra, T., Karlqvist, R., Lassila, I.J., Haeggström, E., Pesonen, L.J. 2011. P- and S-wave velocities of rocks from the upper 1.5 km crustal section sampled by the Outokumpu Deep Drilling Project, Finland. Outokumpu Deep Drilling Project 2003-2010. In: Kukkonen, I. (Ed.). Geological Survey of Finland Special Paper; 51.
  • Elbra, T., Karlqvist, R., Lassila, I.J., Haeggström, E., Pesonen, L.J., 2011. Laboratory measurements of the seismic velocities and other petrophysical properties of the Outokumpu deep drill core samples, eastern Finland. Geophysical Journal International, 184, 405-415.
  • Koskinen, P., Lassila I., Pesonen L.J., 2010. Ultrasonic measurements of P- and S- wave velocities in lower crustal rocks under uniaxial compression. In: Heikkinen, P., Arhe, K., Korja, T., Lahtinen, R., Pesonen, L.J. and Rämö, T., 2010 (Eds). Lithosphere 2010 - Sixth Symposium on the Structure, Composition and Evolution of the Lithosphere in Finland. Programme and Extended Abstracts, Helsinki, Finland, October 27-28, 2010. Institute of Seismology, University of Helsinki, Report S-55, 51-54.
  • Lassila, I., Karlqvist, R., Elbra, T., Gates, F., Pesonen, L.J., Haeggström, E., 2010. Ultrasonic velocity of the upper gneiss series rocks from the Outokumpu deep drill hole, Fennoscandian shield - Comparing uniaxial to triaxial loading. Journal of Applied Geophysics, 72, 178-183.
  • Elbra, T., Lassila, I., Karlqvist, R., Raiskila, S., Haeggström, E., Pesonen, L.J., 2008. Ultrasonic Seismic Velocities in FIRE and ODDP samples, Finland, Fennoscandian Shield. Heikkinen. P., Kukkonen, J.T., Kuusisto, M. and Heinonen, S. (Eds.). In: The 13th International Symposium on Deep seismic Profiling of the Continents and their Margins. Abstracts, Saariselkä, Finland, 8-13 June, 2008. Institute of Seismology, University of Helsinki, Report 5-50, p.16.
  • Pesonen, L.J., Elbra, T., Karlqvist, R., Lassila, I., Haeggström, E., 2008. Seismic velocities of the Outokumpu deep drill core and FIRE profile samples: what do the rocks tell us? In: Korja, T., Arhe, K., Kaikkonen, P., Korja, A., Lahtinen, R. and Lunkka, J.P. (Eds.), Lithosphere 2008, Fifth Smposium on the Structure, Composition and Evolution of the Lithosphere in Finland. Programme and Extended Abstracts, Oulu, Finland, November 5-6, 2008. Institute of Seismology, University of Helsinki, Report 53, 87-90.
  • Hoffren, H., Karppinen T., Kohout T., Haeeggström, E., Pesonen L.J. (2004), Measuring Porosity and Tortuosity of Rocks by Means of Air Ultrasound. Eos Trans. AGU, 85(47), Fall Meet. Suppl., Abstract P33A-0999.