MENLO PARK -- Facebook stock was on a rocket ship Thursday.

Shares in the social networking giant shot up nearly 30 percent, a day after Facebook reported blockbuster earnings that suggest it's beaten the mobile advertising problem that's dogged the company since its disastrous stock market debut last year.

The stock closed Thursday at $34.36, its highest level since Facebook's second day of trading on May 21, 2012. After opening last year at $38, the shares plunged below $20 last summer. But analysts at several Wall Street firms were saying Thursday that the stock could reach $38 or higher in the coming year.

The reason? Facebook said second-quarter revenue climbed 53 percent, to $1.8 billion, as mobile ads grew to account for 41 percent of total ad sales. A year ago, the company was showing no ads on smartphones or tablets, despite the increasing popularity of those gadgets.

"This quarter helps cement the bull thesis and underscores how successful Facebook's transition to mobile has been," Sterne Agee financial analyst Arvind Bhatia wrote to investors Thursday.

Others said Facebook can grow more, since it hasn't even begun selling video ads or ads on its popular Instagram photo service.

Even so, Bernstein Research analyst Carlos Kirjner warned that "questions remain" about whether Facebook can maintain its rate of growth.

Contact Brandon Bailey at 408-920-5022; follow him at Twitter.com/BrandonBailey