In 1997, Barka published a paper with Ross Stein and James H. Dieterich of USGS, titled ""Progressive failure on the North Anatolian Fault since 1939 by earthquake stress triggering"", which showed the migration of large earthquakes and, not surprisingly, positive stress accumulation in the Marmara Region. Only two years after this paper was published, the M7.4 1999 İzmit earthquake hit the Marmara Region, killing more than 17,000 people.