Physics of Earthquakes
During an earthquake, one side of the fault moves suddenly with respect to the other. This process radiates energy as seismic waves, and generates heat due to friction and other non-linear processes. The study of the recent deep Bolivian earthquake suggests that only 4 % of the total strain energy was released as seismic waves, and most of the energy was converted to heat. The total amount of heat energy released is 1 to 10 times more than that released during the major volcanic eruptions such as the 1980 Mt St Helens eruption. This result suggested that melting can be an important mechanism for promoting seismic slip, especially for deep-focus earthquakes.
With the advent of modern broad-band seismic networks we can study seismic wave radiation in detail, from which we can understand how an earthquake nucleates, ruptures, and stops. The goal is to understand the deterministic as well as "complex" aspect of earthquake physics.
- Kanamori, H., and M. Kikuchi, The 1992 Nicaragua Earthquake: a slow tsunami earthquake associated with subducted sediments, Nature, 361, 714-716, 1993.
- Kikuchi, M., and H. Kanamori, The mechanism of the deep Bolivia earthquake of June 9, 1994, Geophys. Res. Lett, 21, 2341-2344, 1994.
- Kanamori, H., D. L. Anderson, and T. H. Heaton, Frictional melting during the rupture of the 1994 Bolivian earthquake, Science, 1998.
Interaction of Atmosphere and Lithosphere
The earth's surface is covered by atmosphere, and energy coupling occurs between atmosphere and lithosphere. For example, during the major eruption of Mount Pinatubo in the Philippines on June 15, 1991, an unusually long (at least two hours) seismic wave train having periods of about 230 sec was recorded at seismic stations throughout the world. This oscillation has a very sharp spectral peak at a period of 228 sec. We found that this wave train is the seismic Rayleigh wave excited by atmospheric oscillations near the volcano that were set off by continuous thermal energy flux from the volcano. This study demonstrated that modern seismological networks can be used to study the physics of volcanic eruptions; it provides new information about how volcanoes affect the Earth's atmosphere and a way to quantify volcanic eruptions. Study of acoustic and gravity waves has interesting applications for understanding unusual waves excited by space shuttles and the impact of the Shoemaker-Levy comet.
- Kanamori, H., J. Mori, D. Anderson, and T. Heaton, Seismic Excitation by the Space Shuttle Columbia, Nature, 349, 781-782, 1991.
- Kanamori, H., and J. Mori, Harmonic Excitation of Mantle Rayleigh Waves by the 1991 eruption of Mount Pinatubo, Philippines, Geophys. Res. Lett., 19, 721-724, 1992.
- Kanamori, H., Excitation of Jovian normal modes by an impact source, Geophys. Res. Lett., 20, 2921-2924, 1993.
- Ingersoll, A. P., and H. Kanamori, Waves from the collisions of Shoemaker-Levy 9 with Jupiter, Nature, 374, 706-708, 1994.
- Kanamori, H., J. Mori, and D. G. Harkrider, Excitation of atmospheric oscillations by volcanic eruptions, J. Geophys. Res., 99, 21,947-21,961, 1994.
Application of Real-Time Seismology to Hazard Mitigation
Advances in seismic sensor and data acquisition systems, digital communications, and computers make it possible to build reliable real-time earthquake information systems. Such systems provide a means for modern urban regions to cope effectively with the aftermath of major earthquakes. While accurate earthquake predictions are difficult, these systems aid in the post-earthquake response and recovery phases, and thus are socially beneficial in modern industrialized urban and suburban regions. In the long term these systems also provide basic data for mitigation strategies such as improved building codes. We are developing a modern seismic network, TriNet, to accomplish this goal. TriNet is a joint project between Caltech, U.S. Geological Survey, and the State of California.
- Kanamori, H., Locating Earthquakes with Amplitude: Application to Real- Time Seismology, Bull. Seismol. Soc. Am., 83, 264-268, 1993.
- Kanamori, H., E. Hauksson, and T. Heaton, Real-time seismology and earthquake hazard mitigation, Nature 390, 461-464, 1997.
Physics of Long-Term Crustal Processes Associated with Earthquakes
The physical properties of the Earth's crust are likely to change as a function of time. However, physics of such changes is not well understood. For example, after the 1992 Landers, California, earthquake, seismic activity in many places in California increased significantly. One interpretation is that the strength of crust was suddenly reduced when it was shaken by passing seismic waves from the Landers earthquake. We have explored a mechanism for such weakening. Although this field is at an early stage of development, a better understanding of the physics of fluid-filled crust would lead to unraveling many interesting, but mysterious, phenomena associated with earthquakes. These phenomena include changes in seismicity, seismicity patterns, electric-magnetic field disturbances, and changes in ground-water level and chemistry.
- Sturtevant, B., H. Kanamori, and E. Brodsky, Seismic triggering by rectified diffusion in geothermal systems, J. Geophys. Res. 101, 25269, 1996.
Please see links above for previous years publications.
Claudio Satriano a, c., n, Yih-MinWub, AldoZollo c, Hiroo Kanamori, 2010, Earthquake early warning: Concepts, methods and physical grounds, Soil Dynamics and Earthquake Engineering
Hauksson, E., Stock, J., Hutton, K., Yang, W., Vidal-Villegas, A. & Kanamori, H., 2010. The 2010 Mw 7.2 El Mayor-Cucapah Earthquake Sequence, Baja California, Mexico and Southernmost California, USA: Active Seismotectonics along the Mexican Pacific Margin, Pure Appl. Geophys., DOI 10.1007/s00024-00010-00209-00027
Hsu, Y.-J., Rivera, L., Wu, Y.-M., Chang, C.-H. & Kanamori, H., 2010. Spatial heterogeneity of tectonic stress and friction in the crust: new evidence from earthquake focal mechanisms in Taiwan, Geophys. J. Int., 182, 329-342, doi: 310.1111/j.1365-1246X.2010.04609.x.
Lay, T., Ammon, C.J., Kanamori, H., Koper, K.D., Sufri, O. & Hutko, A.R., 2010. Teleseismic inversion for rupture process of the 27 February 2010 Chile (Mw 8.8) earthquake, Geophys. Res. Lett., 37, L13301, doi:13310.11029/12010GL043379.
Lay, T., Ammon, C.J., Kanamori, H., Rivera, L., Koper, K.D. & Hutko, A.R., 2010. The 2009 Samoa–Tonga great earthquake triggered doublet, Nature, 466, 964-968, doi: 910.1038/nature09214.
Mello, M., Bhat, H.S., Rosakis, A.J. & Kanamori, H., 2010. Identifying the unique ground motion signatures of supershear earthquakes: Theory and experiments, Tectonophysics, 493, 297-326.
Satriano, C., Wu, Y.-M., Zollo, A. & Kanamori H., 2010. Earthquake early warning:Concepts,methods and physical grounds, Soil Dynamics and Earthquake Engineering, 31, 106-118.
Watada, S. and H. Kanamori 2010. Acoustic resonant oscillations between the atmosphere and the solid earth during the 1991 Mt. Pinatubo eruption . J. Geophys. Res. 115, B12319, doi:12310.11029/12010JB007747.
Zollo, A., Amoroso, O., Lancieri, M., Wu, Y.-M. & Kanamori, H., 2010. A threshold-based earthquake early warning using dense accelerometer networks, Geophys. J. Int., 183, 963-974, doi: 910.1111/j.1365-1246X.2010.04765.x.
Chu, R., S. Wei, Helmberger, D.V., Zhan, Z., Zhu, L. & Kanamori, H., 2011. Initiation of the great Mw 9.0 Tohoku–Oki earthquake, Earth and Planetary Science Letters, 308, 277-283, doi:210.1016/j.epsl.2011.1006.1031.
Duputel, Z., Rivera, L., Kanamori, H., & Hayes, G., 2011. Real-time W phase inversion during the 2011 off the Pacific coast of Tohoku Earthquake, Earth Planets Space, 63, 535-539.
Koper, K. D., Hutko, A.R., Lay, T. Ammon, C.J. & Kanamori, H., 2011. Frequency-dependent rupture process of the 11 March 2011 MW 9.0 Tohoku earthquake: Comparison of short-period P wave backprojection images and broadband seismic rupture models, Earth Planets Space 58, 1-4.
Lay, T., Ammon,C.J., Kanamori, H., Kim, M.J. & Xue, L., 2011. Outer trench-slope faulting and the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake, Earth Planets Space, 63, 713-718, doi:710.5047/eps.2011.5005.5006.
Lay, T., Ammon, C.J., kanamori, H., Xue, L. & Kim, M.J., 2011. Possible large near-trench slip during the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake, Earth Planets Space, 63, 687-692, doi:610.5047/eps.2011.5005.5033.
Lay, T., Ammon, C.J., Kanamori, H., Yamazaki, Y. Cheung, K.F. & Hutko, A.R, (2011). The 25 October 2010 Mentawai tsunami earthquake (Mw 7.8) and the tsunami hazard presented by shallow megathrust ruptures, Geophys. Res. Lett., 38, L06302, doi:06310.01029/02010GL046552.
Lay, T. & Kanamori, H. (2011). Insights from the great 2011 Japan earthquake, Physics Today, 64, December 2011, 33-39.
Lay, T., Yamazaki, Y., Ammon, C.J., Cheung, K.F. & Kanamori, H., 2011. The 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake: Comparison of deep-water tsunami signals with finite-fault rupture model predictions, Earth Planets Space, 797-801, doi:710.5047/eps.2011.5005.5030.
Simons, M., Minson, S., Sladen, A., Ortega, F., Jiang, J., Owen, S., Meng, L, Ampuero, J.P., Wei, S., Chu, R., Hekmberger, D.V., Kanamori, H. Hetland, E., Moore, A.W., Webb, F.H., 2011. The 2011 Magnitude 9.0 Tohoku-Oki Earthquake: Mosaicking the Megathrust from Seconds to Centuries, Science, 332:,1421-1425.
Yamazaki, Y., Lay, T.K.F., Cheung, K. F., Yue, H. & Kanamori, H., 2011. Modeling near-field tsunami observations to improve finite-fault slip models for the 11 March 2011 Tohoku earthquake, Geophys. Res. Lett. 38, L00G15, doi:10.1029/2011GL049130.
Zhao, D., Huang, z., Umino, N., Hasegawa, A. & Kanamori, H., 2011. Structural heterogeneity in the megathrust zone and mechanism of the 2011 Tohokuâ€oki earthquake (Mw 9.0), Geophys. Res. Lett., 38, L17308, doi:17310.11029/12011GL048408.
Colombelli, S., Amoroso, O, Zollo, A & Kanamori, H., 2012. Test of a Threshold-Based Earthquke Early-Warning Method Using Japanese Data, Bulletin of the Seismological Society of America, 102, 1266-1275.
Colombelli, S., Zollo, A, Festa, G. & Kanamori. H., 2012. Early magnitude and potential damage zone estimates for the great Mw 9 Tohoku-Oki earthquake, Geophysical Research Letters, 39, n/a-n/a.
Duputel, Z, Kanamori, H., Tsai, V.C., Rivera, L., Meng, L. Ampuero, J.-P., & Stock, J.M., 2012. Sumatra great earthquake sequence, Earth and Planetary Science Letters, 351-352, 247-257.
Duputel, Z., Rivera, L., Fukahata, Y. & Kanamori, H,, 2012. Uncertainty estimations for seismic source inversions, Geophysical Journal International, 190, 1243-1256.
Duputel, Z., Rivera, L., Kanamori, H. & Hayes, G., 2012. W phase source inversion for moderate to large earthquakes (1990-2010), Geophysical Journal International, 189, 1125-1147.
Kanamori, H., 2012. Earthquake hazards: Putting seismic research to most effective use, Nature, 483, 147-148.
Kanamori, H., Lee, W.H.K. & Ma, K.-F., 2012. The 1909 Taipei earthquake-implication for seismic hazard in Taipei, Geophysical Journal International, 191, 126-146.
Lay, T., Kanamori, H., Ammon, C.J., Koper, K.D., Hutko, A.R., Ye, L., Yue, H. & Rushing, T. M., 2012. Depth-varying rupture properties of subduction zone megathrust faults, Journal of Geophysical Research:Solid Earth, 117, n/a-n/a.
Ritsema, J., Lay, T. & Kanamori, H., 2012. The 2011 Tohoku Earthquake, Elements, 8, 183-188.
Wang, D., Becker, N.C., Walsh, D., Fryer, G.J., Weinstein, S.A., McCreery, C.S., Sardina, V., Hsu, V., Hirshorn, B.F., Hayes, G.P., Duputel, Z., Rivera, L., Kanamori, H., Koyanagi, K.K. & Shiro, B., 2012. Real-time forecasting of the April 11, 2012 Sumatra tsunami, Geophysical Research Letters, 39, n/a-n-a.
Ye, L., Lay, T. & Knamori, H., 2012. Intraplate and interplate faulting interactions during August 31, 2012, Philippine Trench earthquake (Mw7.6) sequence, Geophysical Research Letters, Vol., 2012, 39, L24310 doi:24310.21029/22012GL054164.
Ye, L., Lay, T. & Kanamori, H., 2012. The Sanriku-Oki low-seismicity region on the northern margin of the great 2011 Tohoku-Oki earthquake rupture, Journal of Geophysical Research:Solid Earth, 117, n/a-n/a.
Zhan, Z., Helmberger, D., Simons, M, kanamori, H., Wu, W., Cubas, N., Duputwl, Z., Chu, R., Tsai, V.C., AVouac, J.-P., Hudnut, K.W., Ni, S., Hetland, E. & Culaciati, F.H.O., 2012. Anomalously steep dips of earthquakes in the 2011 Tohoku-Oki source region and possible explanations, Earth and Planetary Science Letters, 353-354, 121-133.