Why some traders warn the selling will continue

After three wretched sessions, stocks kicked off the session with a rally Tuesday, but quickly erased their gains. Some traders say the selling may not be over.

It's been a gut-wrenching few weeks for the market, with the S&P 500 now down 7 percent from its highs, and few signs of a turnaround emerging. The S&P sliced through its widely watched 200-day moving average on Monday, and the selling accelerated late in the session, as the CBOE Volatility Index zoomed to a two-year high. Late pain led the index to close just below 1,875, the lowest level since May.

Read MoreCNBC Explains: The 200-day moving average

S&P futures are gaining slightly in early trading. As third-quarter earnings season began, Tuesday morning results from JPMorgan, Citigroup and Johnson & Johnson have beaten expectations. Yet traders warn that technical indicators may outweigh good earnings new in the near term.

The selling "may not continue into today—but I don't think it's over," Anthony Grisanti of GRZ Energy wrote to CNBC. "Technicals alone point to a lower market. It looks like we are headed for a 10 percent adjustment."

Notably, the S&P has not suffered a 10 percent correction since summer of 2011. Many have long called such an event overdue.

Read MoreWall Street hopes for a boost from earnings

"Yesterday's late-day weakness leads me to believe that the correction is not over yet," Jim Iuorio of TJM Institutional Services wrote on Tuesday morning. "I expect the S&P futures to trade down near 1,800 before attempting to build a base."

Yet, Iuorio added, "I do believe this is a correction and not indicative of a bear market," given that the Federal Reserve continues to be involved as it keeps its target federal funds rate ultra-low.

Read MoreHere's why this drop is not like the others: Trader

Of course, not everyone predicts that there's more pain to come.

"Really severe breaks don't happen in a vacuum," said Scott Nations of NationsShares. "Absent a data catalyst, I don't see the break getting dramatically worse."

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