The Insurance Information Institute warned today that the severe earthquake in Haiti is a reminder that the United States is vulnerable to the same type of catastrophe and is woefully underinsured.

I.I.I. noted that the potential cost of U.S. earthquakes has been growing because of increasing urban development in seismically active areas and the vulnerability of older buildings, which may not have been built or upgraded to current building codes.

Compounding this problem, it said, is the fact that the vast majority of homeowners living in seismic zones do not purchase earthquake insurance. In California, it was noted, only 12 percent of California homeowners have earthquake coverage.

Coverage is usually available for earthquake damage in the form of a supplemental policy to homeowners or business insurance, I.I.I. said. It added that standard homeowners and business insurance policies may, however, cover losses from a fire following an earthquake, which would include additional living expenses and business interruption coverage.

Cars and other vehicles are covered for earthquake damage under the optional comprehensive portion of an auto insurance policy.

Earthquake insurance policies, said I.I.I., often carry a deductible, generally in the form of a percentage rather than a dollar amount. Deductibles can range anywhere from 2 percent to 20 percent of the structure's replacement value. This means that if it costs $100,000 to rebuild a home and the policy had a 2 percent deductible, the policyholder would be responsible for paying the first $2,000.

California homeowners can secure coverage from the privately funded, publicly managed California Earthquake Authority. CEA offers homeowners dwelling coverage deductibles of either 10- or 15 percent. The CEA coverage limit is the insured value of the home as stated on the companion homeowners insurance policy.

I.I.I. mentioned that last week’s Haitian earthquake is being compared to that of the quake that struck Haiti in 1842, killing thousands, and noted that there is little awareness in the United State that the country was also rocked by a huge quake in  1811.

The New Madrid earthquake of December 1811, I.I.I. said, was one of the largest in U.S. history, with its epicenter in Missouri and a shock wave that rang church bells in Boston, more than 1,000 miles away.

New Madrid Fault zone lies within the central Mississippi valley extending from northeastern Arkansas through southeastern Missouri, western Tennessee, Kentucky and southern Illinois. Indeed, four small quakes in mid-December 2009 were felt in Arkansas, Missouri, Tennessee and Kentucky, even though the highest magnitude was only a 3.1, versus the 7.0 temblor which hit Haiti.

Since 1900, earthquakes have occurred in 39 U.S. states. Minor earthquakes, for instance, struck states such as Illinois and Nevada in 2008. There has not been a major quake on the U.S. mainland, however, since the 6.7 magnitude Northridge, Calif., event in 1994, I.I.I. reminded.

It said California remains the U.S. state most at risk of a major earthquake, and a huge quake is more likely in Southern California than in Northern California over the next 30 years, according to a study by the 2008 U.S. Geological Survey, Southern California Earthquake Center and California Geological Survey.

That report also predicted, in looking at the 30-year probability of one or more events greater than or equal to the magnitude of the Northridge quake hitting California, that there is a 99 percent chance that at least one earthquake meeting that criterion will occur.

The 1994 Northridge earthquake and the 1989 6.9 magnitude Loma Prieta quake that struck the Oakland-San Francisco area during that year’s World Series were the two most costly earthquakes in U.S. history, as defined by insured losses.

In 2008 dollars, Northridge caused an estimated $19-to-$29 billion in insured losses, while the Oakland-San Francisco quake resulted in insured losses totaling a little over $12 billion, said I.I.I.

But, almost 16 years after 1994’s Northridge earthquake, only about one in eight California residents have their homes or businesses insured for property losses in the event of a quake, the Insurance Information Network of California estimated.

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