The year 2011 marks the 200th anniversary of the first in a sequence of three Magnitude 7 or greater earthquakes that occurred over a 54-day period spanning 1811 to 1812 along the Mississippi River, near the town of New Madrid, Missouri. Ground shaking from the three main shocks – which struck on December 16, 1811, January 23, 1812, and February 7, 1812 – was experienced over the entire Eastern U.S., up to 1400 km from the epicenters. The earthquakes also created hundreds of aftershocks, which were felt for months afterwards. A high level of seismicity persists in the New Madrid Seismic Zone (NMSZ) region today, with this activity considered by some to be part of the continuing aftershock series. Seismicity rate estimates suggest a 28–46% likelihood of a M6.0 or greater earthquake in the broad region around New Madrid in the next 50 years.
In a new report, RMS has analyzed a range of earthquake scenarios in the New Madrid region. The analysis reveals that if a similar, even moderate, earthquake (M6.1–6.5) were to occur adjacent to a major urban area today, it would generate total economic losses in the range of $10 to $100 billion and insured losses of $5 to $50 billion. The range depends on the degree to which ground shaking decays with distance from the earthquake source, which remains a key area of uncertainty. It is forecast that insurance payments would cover 60–80% of total economic losses, therefore contributing significantly to recovery efforts. This ratio of insured to total economic loss is higher than the 45–55% ratio observed in hurricanes Ike (2008), Katrina (2005) and Andrew (1992), and significantly larger than the anticipated ratio of 10–15% for major California earthquakes.
“The 200th anniversary of the 1811–1812 New Madrid earthquake sequence is a stark reminder of the earthquake risk in the region, the potential losses that could occur, and the need to adequately prepare for a possible future event,” noted Dr. Patricia Grossi, director of research at RMS and co-author of the study.
Source : RMS