Authorities suggest you ask for the name of the charity and how much of your money will go to relief efforts. Don't hand over your bank or credit card information unless you're positive the group is legitimate, and always ask for a receipt.
The best way to help is primarily by donating cash, said Capt. Mike Parker of the Sheriff's Headquarters Bureau.
A list of of nonprofit charities working with the Japanese government is available on the website of the U.S. Agency for International Development, www.usaid.gov.
People interested in volunteering should go to www.CaliforniaVolunteers.org and enter your ZIP code.
City News Service contributed to this report.
