Roger-see Lowell's note. It looks like the Lat-Long coordinates are not in his thesis. So, go with New Guinea to New Britain and maybe 1 or 2 deg of Latitude and longitude around them. Go with southern California south of 35 deg (or 36 deg of you prefer, to include Coso etc.). Include offshore to 121 deg west.

Choose you preferred way to graph this-maybe look at the Physics Today article. Chris