The 5.4 earthquake that rattled Southern California yesterday didn’t damage any cell sites or towers. But the networks became so jammed that they were unable to process all of call volumes, according to the Los Angeles Times.

According to a Sprint spokeswoman, Sprint’s networks experienced an 800% call spike. Verizon Wireless also experienced unprecedented call volumes, more than it would normally expect in association with emergency situations.

Wireless networks weren’t the only ones overwhelmed. Landline customers had problems as well. Many customers reported busy signals or no dial tones.

Call volumes returned to normal by mid-afternoon.