NEW YORK -- Cable stocks surged Thursday as investors responded both to strong quarterly earnings reports from cable operators and legendary investor Warren Buffett's move into the cable sector.

Buffett said Wednesday he had accumulated 8.1% of TCA Cable, a low- profile Texas cabler, in what is thought to be the billionaire investor's first try at cable. Wall Streeters said Buffett had been buying TCA steadily for the past 12 months.

Analysts said the investment was yet another affirmation of cable's prospects, two years after Buffett's friend, Microsoft chairman Bill Gates, decided to invest $1 billion in Comcast and a year after Microsoft co-founder Paul Allen also started buying up cable systems. TCA stock rose $1.06 to $44.18 Thursday after gaining 16% Wednesday.

Other cable stocks rose even more dramatically Thursday. Comcast Corp. stock rocketed $3.75 or 5.6% to $70.87 after the cabler said it would buy a 79,000-subscriber system in Philadelphia from Greater Media Inc. for stock valued at $297 million.

The Philadelphia system plugged a hole in Comcast's Philadelphia-area cable systems and at a good price, according to SG Cowen analyst Gary Farber. "Comcast is trading at 18 times cash flow and they bought the system at 13 times," Farber said. (Cash flow is earnings before interest, taxes, depreciation and amortization).

Cox Communications, whose stock jumped $5.50 to $73, reported after the market closed 17% higher fourth- quarter cash flow of $199.1 million on 16% higher revenue of $486.7 million.Cox CEO Jim Robbins said the result reflected both strong customer growth and the impact of new services like digital cable and high-speed Internet access on earnings.

Likewise, Jones Intercable said its fourth-quarter cash flow rose 15% to $69.5 million on 7% higher revenue of $131 million. Jones' stock price closed up $1.68 to $39.18.

And despite a less spectacular quarterly performance, MediaOne Group's stock price rose 81� to $55.56. Media One said cash flow in the fourth quarter was flat at $235 million on 11% higher revenue of $627 million, adjusted for acquisitions.

Also sharing in the cable stock rise was Tele-Communications Inc., due to be acquired by AT&T in the next few weeks. Its stock rose $1.50 to $65.81.