Much of the destruction caused by a nuclear explosion is from blast effects. Most buildings, except reinforced or blast-resistant structures, will suffer moderate damage when subjected to overpressures of only 35.5 kilopascals (kPa) (5.15 pounds-force per square inch or 0.35 atm). Data obtained from Japanese surveys following the atomic bombings of Hiroshima and Nagasaki found that 8 psi (55 kPa) was sufficient to destroy all wooden and brick residential structures. This can reasonably be defined as the pressure capable of producing severe damage.