Complex sentence: Within the first several decades of the event, Koto and Omori documented the comprehensive fault breaks that were visible on the surface, and a later investigation by T. Matsuda revealed that the breaks followed a general northwest-southeast trend.
Split into simpler sentences: Within the first several decades of the event, Koto and Omori documented the comprehensive fault breaks that were visible on the surface. A later investigation by T. Matsuda revealed that the breaks followed a general northwest-southeast trend.