In recognition of his significant contributions to the field of geology and volcanology. His PhD dissertation established the origin by seafloor-spreading of the Andaman Basin between Burma,
the Malay Peninsula, Sumatra and the Andaman-Nicobar island chain. This anticipated the plate tectonic model and was praised for its foresight. His deep-sea drilling research in the Philippine Sea in 1978 showed that cycles of arc sundering in the Marianas Island region precede and follow episodes of arc volcanism, instead of being penecontemporaneous with them, contrary to the prevailing model; this was confirmed eight years later.  His studies with Filipino scientists on the Mayon and Pinatubo lahars— their triggering mechanisms, flow behavior, and previous occurrences,
have educated the Filipinos and the national leadership about lahars, which is crucial for disaster planning and management.  His pioneering work on land subsidence and the resulting flooding
and tidal incursions in the country is particularly timely. His research is documented in more than 90 scientific articles in national and international refereed journals, books and proceedings
and presented at many conferences all over the world. A five-time recipient of the University of Illinois at Chicago Excellence in Teaching Award, he has mentored about 190 undergraduate and 12
graduate geology and environmental science students, including several Filipinos, a good number of whom are now experts and leaders in the field.