Scientists have warned that Tehran could be next in line because of its location in a high-risk fault zone. An expert at the Moroccan National Centre for Earthquake Research, Nasir Jabbur, says the Sumatra quake responsible for the December 2004 tsunami has accelerated the frequency of tremors along these fault lines. "This is one of the reasons why Iran has witnessed two devastating earthquakes in just over a year. And today's quake is only 250km away from the epicentre of Bam. Tehran is about 700km from the epicentre of the Zarand quake and could be next in line," Jabbur said. Many seismologists suggest Tehran is especially vulnerable to a big quake due to the fact that the city straddles several major fault lines and has not experienced a substantive tremor since 1830.