An anonymous reader quotes a report from Los Angeles Times: A new study suggests that the 1933 Long Beach earthquake, the deadliest seismic event in recorded Southern California history, may have been caused by deep drilling in an oil field in Huntington Beach. The study, written by two leading U.S. Geological Survey scientists in Pasadena and to be published in the Bulletin of the Seismological Society of America on Tuesday, also suggests that three other earthquakes, including magnitude 5.0 earthquakes in 1920 in Inglewood and in 1929 in Whittier, may also be linked to oil drilling. The two government scientists, Susan Hough and Morgan Page, wrote the report after a review of nearly forgotten state oil drilling records. They discovered that the epicenter of some of the Los Angeles Basin's largest earthquakes between 1900 and 1935 happened shortly after significant changes were made in oil production in nearby fields. During this era, the Los Angeles area was one of the world's leading oil producers. The report's finding does not mean that oil drilling is causing earthquakes in Southern California today. The study only focused on earthquakes between 1900 and 1935. Different scientists have looked at earthquakes during more recent decades and have not found any reason to blame oil production for triggering earthquakes more recently in the L.A. Basin. The reason could be that oil drilling practices in the L.A. Basin have changed dramatically since the years when oil was first discovered in this region, and today's techniques may be safer and thus unlikely to trigger earthquakes as they might have done long ago. The Long Beach earthquake killed about 120 people and caused major damage throughout the region. It was named the Long Beach earthquake because the worst damage occurred in that city, even though the epicenter of the earthquake was actually in the Huntington Beach area. The quake destroyed many brick buildings, and prompted officials to ban new construction of unreinforced brick buildings.