California Code, Health and Safety Code - HSC § 103450

(a) A verified petition may be filed by any beneficially interested person with the clerk of the superior court in and for (1) the county in which the birth, death, or marriage is alleged to have occurred, (2) the county of residence of the person whose birth or marriage it is sought to establish, or (3) the county in which the person was domiciled at the date of death for an order to judicially establish the fact of, and the time and place of, a birth, death, or marriage that is not registered or for which a certified copy is not obtainable.

(b) In the event of a mass fatalities incident, a verified petition may be filed by a coroner, medical examiner, or any beneficially interested person with the clerk of the superior court in and for (1) the county in which the death is alleged to have occurred, or (2) the county in which the person was domiciled at the date of death for an order to judicially establish the fact of, and the time and place of, a death that is not registered or for which a certified copy of the death certificate is not obtainable.

(c) In the event of a mass fatalities incident, a single verified petition with respect to all persons who died may be filed by a coroner or medical examiner with the clerk of the superior court in and for the county in which the mass fatalities incident occurred for an order to judicially establish the fact of, and the time and place of, each person's death that is not registered or for which a certified copy of the death certificate is not obtainable.