Mezue nkebi ahịrịokwu na-esonụ: Ala ọma jijiji na-emekarị na Los Angeles n'ihi na ọ dị n'ebe a na-akpọ Pacific Ring of Fire. Enweghị nkwụsi ike nke mbara ala emewo ka e nwee ọtụtụ mmebi, bụ́ ndị na-akpata ihe dị ka ala ọma jijiji 10,000 kwa afọ n'Ebe Ndịda California, ọ bụ ezie na ihe ka ọtụtụ n'ime ha dị nnọọ obere nke na a dịghị enwe mmetụta ha. Usoro mmebi San Andreas, nke na-anọdụ n'ókè dị n'etiti Pacific Plate na North American Plate, na-agafe n'ógbè Los Angeles. Akụkụ nke mmebi ahụ na-agafe na Southern California na-enwe ala ọma jijiji dị ukwuu ihe dị ka afọ 110 ruo 140 ọ bụla, ndị ọkà mmụta banyere ala ọma jijiji adọwokwa aka ná ntị banyere "nnukwu" nke na-abịanụ, ebe ọ bụ na ala ọma jijiji ikpeazụ dị ukwuu bụ ala ọma jijiji Fort Tejon nke 1857. Ókèala Los Angeles na ógbè ndị dị n'ime ya nọkwa n'ihe ize ndụ nke oké ala ọma jijiji. Nnukwu ala ọma jijiji ndị meworo n'ógbè Los Angeles gụnyere nke mere na Long Beach n'afọ 1933,
1971 San Fernando, 1987 Whittier Narrows, na ihe omume 1994 Northridge. Ọ bụ nanị ole na ole n'ime ha ka a na-anaghị enwe mmetụta ha n'ahụ́ mmadụ. USGS ewepụtala amụma ala ọma jijiji nke UCERF California, nke na-eme ka ala ọma jijiji na California. Akụkụ nke obodo ahụ na-enwekwa ike ịba na tsunamis; e mebiri ebe ndị dị n'ọdụ ụgbọ mmiri site na ebili mmiri site na ala ọma jijiji Aleutian Islands na 1946, ala ọma jijiji Valdivia na 1960, ala ọma jijiji Alaska na 1964, ala ọma jijiji Chile na 2010 na ala ọma jijiji Japan na 2011.