I have wondered that myself, so when I saw your question I googled the date. It coincides with a great deal of earthquake activity in California. It seems plausible that there was a lot of fear in the population on that date. People may have drank to cope with the fear or perhaps found themselves wanting to drink in response to the stress and fear from all those earthquakes. As a result they might have come to this web site as a result of drinking or to help them not drink. I was not living in California in 2012, but I was in the San Fernando Valley during the Northridge quake of 1994. The amount of fear following quakes can be palpable.
Absent anything better, this is what now seems like most plausible explanation. I would be very curious what Anna would say in response to your question, both because she in an admin. here at SR and also because (if memory serves) she lives in Southern California.