b'PeopleNewsa new style of images in terms of bulk-sound speed and shear wavespeed were developed for the whole Earth, which provided new information on the nature of heterogeneity at smaller scales. The tomography results have been greatly aided by the development of self-consistent global models for radial earth structure working with Dr E R Engdahl at the US Geological Survey in Golden, Colorado. The iasp91 model, published in 1991, allowed better locations to be found for many seismic events, particularly in depth. As a result, a new set of empirical travel times for the major seismic phases were built, and these formed the basis of the improved ak135 model published in 1995. These reference models have become the standard for body wave tomography, and are now used by all the major international agencies for earthquake location.Brian Kennett getting somewhat damp whilst carrying out field work at the ANU Coastal Campus at Kioloa With the improved travel time models it became worthwhile to revisit methods shutter-blind across the USA over thehas proved to be very powerful andfor global earthquake location, and a 10year period from 2005-2015. has been extensively used for inversionnumber of different procedures were The high quality portable instrumentsof teleseismic data from the WOMBATdeveloped based on homing-in on the record continuously, and so a verydeployments. best solution in 4-dimensional space-large amount of data is available fortime. The most consistently effective subsequent analysis. A wide range ofAlongside the regional studies, effortsapproach uses the Neighbourhood techniques have been used to look athave been made to look at high- Algorithm developed by Malcolm structure beneath the Australian region.resolution body wave tomography on aSambridge, and this is now employed In the period from 1998-2005 thereglobal scale starting with the PhD projectwithin the location procedure used by was particular emphasis on surfaceof Sri Widiyantoro, jointly supervisedthe International Seismological Centre. wave tomography, with both practicalwith Rob van der Hilst. In this work aCoupled with ray-tracing in a full 3-D and theoretical advances made in thedetailed set of regional models of 3-Dmodel the Neighbourhood Algorithm PhD projects of K Yoshizawa and SP wavespeed were developed for theapproach has proved to be very effective Fishwick, building on the work of formermajor subduction zones around theat the continental scale since, e.g., it Postdoctoral Fellow E Debayle. The highlyglobe, and then a full global model wasis possible to take into account the favourable distribution of earthquakecreated. By undertaking joint inversionvery fast wavespeeds beneath western sources around the Australia continentof P and S wave arrival time information,Australia.means that we have been able to use information from higher-frequency body waves to provide independent information and checks on the results from the surface wave work. The inferences from the various sources of data are very consistent and provide confidence in the accuracy of the results.I became interested in the problems of earthquake location when I acquired responsibility for the southeast Australian network on arrival at ANU, and this also led into regional scale seismic tomography. Malcolm Sambridge and I developed a fully non-linear approach to event location tracking to the best solution in space-time. With improved earthquake location it was possible to determine a 3-D model of the P wave structure across the SE Australia using a sub-space projection method to reduce computational demands. This approachBrian Kennett in 2005 with a poster on great Sumatran Earthquake15 PREVIEW APRIL 2019'