The IASPEI Medal 2019 was awarded during the Opening Plenary at the General Assembly in Montréal to Brian Leslie Norman KENNETT, who could unfortunately not attend. Brian sent instead his acceptance speech as a video message, which was shown during the plenary. The laudation was given by Prof. Kazuki Koketsu, Japan.
Brian received his Ph.D. in Theoretical Seismology from the University of Cambridge in 1973. He was a Lindemann Fellow at IPGP, University of California, San Diego and Lecturer at the University of Cambridge from 1976 to 1984. He moved to the Research School of Earth Sciences (RSES), Australian National University (ANU) in 1984 and engaged in research and education as a fellow, professor, and director. He was Director of RSES from September 2006 to January 2010 and Director of the Australian National Seismic Imaging Resource (ANISR) from 2002 to 2014. He is currently Emeritus Professor of Seismology, ANU College of Science.
During his doctoral studies at Cambridge, Brian developed a novel method named the wave propagator to compute seismograms in layered models with control of reverberations of up-going and down-going waves in layered media. He combined this with observational studies of seismic waves across a wide range of distance scales - from a few kilometers, as in shallow reflection experiments for geophysical prospecting, to regional and teleseismic distances for representing a class of seismic phenomena due to large-scale layering in the earth. After moving to Australia, he conducted a systematic study of the Australian region by deploying many large-scale broadband seismic arrays; notably the SKIPPY project in collaboration with Rob van der Hilst. Following a sequence of efforts, this resulted in the 2012 Australian Seismological Reference Model (AuSREM).
Brian’s innovations in theoretical seismology (including his profound and wide-ranging observational studies, ranging across the regional and teleseismic wavefield) aimed at extracting detailed information regarding the nature of Earth’s structure and the character of seismic sources, have had a lasting, significant impact on geophysics.
One of his notable contributions to seismology is the construction of a global traveltime table (iasp91) with Bob Engdahl, which provides accurate estimates of the traveltimes of various seismic phases, significantly improving upon the classic Jeffreys-Bullen traveltime tables. The significance of this study is evidenced by the fact that there are over 2,100 citations of this paper to date. The iasp91 traveltime tables, which was subsequently improved with additional seismic data (giving the ak135 tables), have now become the standard for international organizations like ISC, USGS NEIC and EMSC, as well as for many researchers when determining source locations using seismic phases; they are also extensively used as the reference structure for high-resolution seismic tomography using many seismic phases.
Brian’s development of joint seismic tomography, using P-?and?S-wave arrival-time data, led to the extraction of the distribution of bulk and shear moduli at depth. This enabled the quantitative interpretation of heterogeneous Earth structures in terms of thermal and compositional variations. The results of tomography at higher frequencies, with a particular emphasis on fine-scale heterogeneities in the Earth, lead to efforts among seismologists, mineral physicists, and geodynamicists to interpret the nature and origin of lithospheric heterogeneities.
The publication of his many textbooks on the seismic wavefield and crustal structure based on his excellent wide-ranging theoretical and observational studies has greatly contributed to dissemination of seismological theory and research results and the development of new quantitative waveform modeling approaches.
Brian has been an outstanding leader in support of the international community as president of the IASPEI from 1999 to 2003 and editor of Geophysical Journal International (for more than 20 years), Physics of the Earth and Planetary Interiors, and Earth and Planetary Science Letters.
Among his awards and recognitions are the University of Cambridge Smith’s Prize and Adam’s Prize, and election to Fellow of the American Geophysical Union, Australian Academy of Sciences, Royal Society, and Royal Astronomical Society. He received the Jaeger Medal for Australian Earth Sciences from the Australian Academy of Sciences, the Murchison Medal of the Geological Society of London, the Gutenberg Medal of the European Geosciences Union, the Finders Medal of the Australian Academy of Sciences, and the Lehmann Medal of the American Geophysical Union.
In recognition of the profound seismological contributions of Brian Kennett, it is with great pleasure that he is awarded the 2019 IASPEI Medal.
Takashi Furumura, Kazuki Koketsu and the IASPEI Bureau