June 23, 1915 Earthquake: El Centro, California, United States

2925. June 22. El Centro, Calexico, and Mexicali. Two destructive shocks, nearly 1 hour apart. Heavy damage (about $900,000) in southern Imperial Valley was caused as much by poor quality of buildings as by the intensity of shock. In El Centro, well constructed buildings merely suffered cracks. At Mexicali, Mexico, people returned to buildings after the first shock; six were killed and many were injured by the second earthquake. Though a few cracks were formed in the alluvium, the irrigation ditches and works were damaged very little. The unstable banks of the New and Alamo Rivers slid down in many places. Several farmers observed that after the shocks, one-third more water was required for irrigation because of the cracks in the soil. Despite the rather high local intensity, the total energy was moderate. Magnitude 6% for both shocks. (reference #1128)

1915 June 22. El Centro, Calexico, and Mexicali; 2 destructive shocks, nearly 1 hour apart. Heavy damage in southern Imperial boom period as to intensity of shock. In El Centro well-constructed buildings merely suffered cracks. At Mexicali people returned to buildings after the first shock and 6 were killed and many injured. Though a few cracks mere formed in the alluvium, the irrigation ditches and works mere little damaged. The unstable banks of the New and Alaino Rivers slid down in many places. Several farmers observed that after the shocks one-third more water was required for irrigation, because of the cracks in the soil. Area affected was about 50,000 square miles. Despite the rather high local intensity, the total energy was moderate. (reference #1074)