U.S. most vulnerable reactor: Indian Point 3, N.Y.

Palisades, Covert, Mich.: 1 in 156,250 chance each year. Old estimate: N/A. Change in risk: N/A.

78. South Texas 1, Bay City, Texas: 1 in 158,730 chance each year. Old estimate: 1 in 1,298,701. Change in risk: 718 percent.

78. South Texas 2, Bay City, Texas: 1 in 158,730 chance each year. Old estimate: 1 in 1,298,701. Change in risk: 718 percent.

80. FitzPatrick, Scriba, N.Y.: 1 in 163,934 chance each year. Old estimate: 1 in 833,333. Change in risk: 408 percent.

81. Byron 1, Byron, Ill.: 1 in 172,414 chance each year. Old estimate: 1 in 1,470,588. Change in risk: 753 percent.

81. Byron 2, Byron, Ill.: 1 in 172,414 chance each year. Old estimate: 1 in 1,470,588. Change in risk: 753 percent.

83. Surry 1, Surry, Va.: 1 in 175,439 chance each year. Old estimate: 1 in 123,457. Change in risk: -30 percent.

83. Surry 2, Surry, Va.: 1 in 175,439 chance each year. Old estimate: 1 in 123,457. Change in risk: -30 percent.

85. Nine Mile Point 2, Scriba, N.Y.: 1 in 178,571 chance each year. Old estimate: 1 in 1,000,000. Change in risk: 460 percent.

86. Browns Ferry 2, Athens, Ala.: 1 in 185,185 chance each year. Old estimate: 1 in 625,000. Change in risk: 238 percent.

86. Browns Ferry 3, Athens, Ala.: 1 in 185,185 chance each year. Old estimate: 1 in 625,000. Change in risk: 238 percent.

88. Nine Mile Point 1, Scriba, N.Y.: 1 in 238,095 chance each year. Old estimate: 1 in 1,724,138. Change in risk: 624 percent.

88. Fermi 2, Monroe, Mich.: 1 in 238,095 chance each year. Old estimate: 1 in 625,000. Change in risk: 163 percent.

90. Arkansas Nuclear 1, London, Ark.: 1 in 243,902 chance each year. Old estimate: 1 in 1,063,830. Change in risk: 336 percent.

90. Arkansas Nuclear 2, London, Ark.: 1 in 243,902 chance each year. Old estimate: 1 in 1,063,830. Change in risk: 336 percent.

92. Comanche Peak 1, Glen Rose, Texas: 1 in 250,000 chance each year. Old estimate: 1 in 833,333. Change in risk: 233 percent.

92. Comanche Peak 2, Glen Rose, Texas: 1 in 250,000 chance each year. Old estimate: 1 in 833,333. Change in risk: 233 percent.

94. Browns Ferry 1, Athens, Ala.: 1 in 270,270 chance each year. Old estimate: 1 in 1,000,000. Change in risk: 270 percent.

95. Prairie Island 1, Welch, Minn.: 1 in 333,333 chance each year. Old estimate: 1 in 714,286. Change in risk: 114 percent.

95. Prairie Island 2, Welch, Minn.: 1 in 333,333 chance each year. Old estimate: 1 in 714,286. Change in risk: 114 percent.

97. La Salle 1, Marseilles, Ill.: 1 in 357,143 chance each year. Old estimate: 1 in 1,851,852. Change in risk: 419 percent.

97. La Salle 2, Marseilles, Ill.: 1 in 357,143 chance each year. Old estimate: 1 in 1,851,852. Change in risk: 419 percent.

97. Hope Creek 1, Hancocks Bridge, N.J.: 1 in 357,143 chance each year. Old estimate: 1 in 909,091. Change in risk: 155 percent.

100. Clinton, Clinton, Ill.: 1 in 400,000 chance each year. Old estimate: 1 in 370,370. Change in risk: -7 percent.

101. Shearon Harris 1, New Hill, N.C.: 1 in 434,783 chance each year. Old estimate: 1 in 277,778. Change in risk: -36 percent.

102. Hatch 1, Baxley, Ga.: 1 in 454,545 chance each year. Old estimate: 1 in 1,351,351. Change in risk: 197 percent.

102. Hatch 2, Baxley, Ga.: 1 in 454,545 chance each year. Old estimate: 1 in 1,351,351. Change in risk: 197 percent.

104. Callaway, Fulton, Mo.: 1 in 500,000 chance each year. Old estimate: N/A. Change in risk: N/A.

These risk estimates consider how violently the ground will shake at the nuclear plant. The shaking can be affected by the depth, distance from the epicenter, and the frequencies of waves that the quake emits. The shaking is expressed in a unit called peak ground acceleration, a measurement of intensity.