article_snippet: Scientists are virtually certain that California will be rocked by a strong earthquake in the next 30 years.
article_snippet: Now Scientists say the risk of a mega-quake is more likely than previously thought.
article_snippet: The chance of a magnitude-8 quake striking California in the next three decades jumped to 7 per cent from 4.7 per cent, mainly because scientists took into account the possibility that several faults can shake at once, releasing seismic energy that results in greater destruction.
article_snippet: While the risk of a mega-quake is higher than past estimates, the risk of a mega-quake's more likely - greater than 99 per cent chance - that California will be rattled by a magnitude-6.7 jolt similar in size to the 1994 Northridge disaster.
article_snippet: A new U.S. Geological Survey report has increased the likelihood of a magnitude-8 earthquake hitting California over the next 30 years.
article_snippet: Above, a photo of an overpass that collapsed in the 1994 magnitude-6.7 Northridge earthquake .
article_snippet: The chance of a Northridge-size quake was slightly higher in Northern California than Southern California - 95 per cent versus 93 per cent, according to a report released Tuesday by the U.S. Geological Survey. '
article_snippet: California is earthquake country, and residents should live every day like it could be the day of a big one,' USGS geophysicist and lead author Ned Field said.
article_snippet: Back then, scientists also determined that California faced an almost certain risk of experiencing a Northridge-size quake.
article_snippet: Because of this knowledge, the odds of a catastrophic quake - magnitude 8 or larger - in the next 30 years increased.
article_snippet: There is a 93 per cent chance of a magnitude 7 or larger occurring over the same period and a 48 per cent chance of a magnitude 7.5 - similar to previous estimates.
article_snippet: Thousands of quakes every year hit California, sandwiched between two of Earth's major tectonic plates, the Pacific and North American plates.
article_snippet: Of the more than 300 faults that crisscross California, the southern segment of the San Andreas Fault - which runs from central California to the Salton Sea near the U.S.-Mexico border - remains the greatest threat because it hasn't ruptured in more than three centuries.
article_snippet: a report released Tuesday by the U.S. Geological Survey found there is a 19 per cent chance in the next 30 years that a Northridge-size quake will unzip the southern section compared to a 6.4 per cent chance for the northern section, partly because a report released Tuesday by the U.S. Geological Survey last broke in 1906.
article_snippet: The southern San Andreas is 'ready to have an earthquake because an earthquake's really locked and loaded,' Field said.
highlights_snippet: New U.S. Geological Survey report increases chances of magnitude-8 earthquake in next three decades to 7 per cent, up from 4.7 per cent .