Across the world, cities keep growing on top of active faults, and the difference between a scary day and a mass-casualty event comes down to construction quality, building codes, and how seriously owners treat retrofit work.
WorldAtlas points to one of the clearest U.S. lessons from masonry history. In 1933, a magnitude 6.4 earthquake struck near Long Beach, California, killing between 115 and 120 people and causing about $40 million in damage. Many deaths happened after unreinforced masonry fell on people who ran into the street. The quake reshaped California’s building rules, and the Field Act still guides how schools get built in the state.
That same building type shows up again in today’s retrofit conversation. The article notes that the Seattle Fault runs under part of downtown, and a 2002 study estimated a magnitude 7 event would damage more than 80 bridges in the Seattle-Tacoma area. Those kinds of projections helped drive ongoing efforts to retrofit unreinforced masonry buildings. In the Bay Area, attention has shifted to the Hayward Fault, and the region has invested heavily in retrofitting bridges, freeways, and older buildings.
Internationally, the story contrasts places that moved fast with places still exposed. Tokyo turned the 1923 Great Kanto Earthquake into a century of seismic engineering, including base isolators and tuned mass dampers. Wellington, New Zealand, sits on the Wellington Fault and enforces one of the strictest building codes in the world. Christchurch shows a different risk, hidden faults that were not mapped before the 2010 and 2011 quakes that devastated the central business district.
Other cities face seismic danger with weaker safeguards. WorldAtlas describes slow, uneven rebuilding after Nepal’s 2015 magnitude 7.8 Gorkha earthquake, and it cites a 2023 study warning that a large quake in Tehran would collapse many buildings tied to rapid growth and weak permitting. From Istanbul to Mexico City to Beirut, the article’s bottom line stays the same: the ground moves on its own schedule, but strong codes, early-warning systems, and consistent enforcement shape what survives.
Read the full, original article from WorldAtlas here.