From a article in USAToday, using data from the insurance co. Swiss Re; fortunately, only one of these is in the U.S. No others are in North America.

World’s most vulnerable cities, with population:

• Tokyo-Yokohama, Japan (57.1 million)
• Manila, Philippines (34.6 million)
• Pearl-River Delta, China (34.5 million)
• Osaka-Kobe, Japan (32.1 million)
• Jakarta, Indonesia (27.7 million)
• Nagoya, Japan (22.9 million)
• Kolkata, India (17.9 million)
• Shanghai, China (16.7 million)
• Los Angeles (16.4 million)
• Tehran, Iran (15.6 million)

There also is a 36 page report that provides more details, available at this site.  There are smaller reports for various continents available also.