* Nikkei sinks below support at 9,612.51
* Nikkei's mid-term support seen book value at 8,800-analyst
* Strong aftershocks keep investors on edge -fund manager
* Selling in blue-chip shares as earnings worries weigh
* Oil, gas stocks track commodities decline
By Ayai Tomisawa and Antoni Slodkowski
TOKYO, April 12 (Reuters) - Tokyo stocks tumbled, dropping for a second straight day on Tuesday, on growing worries that the impact of the March 11 earthquake may be more severe than hoped for and as Japan put its nuclear crisis on par with Chernobyl.
Car and electronics makers were sold off while declines in oil prices spurred profit-taking in energy-related shares, pushing the Nikkei stock average below key support of 9,612.51, where April options settled last week.
"The market had until now thought that the quake's impact would be felt most severely in the April-June quarter, but it seems it may drag on for at least another quarter, and will keep the market depressed for much longer," said Hideo Arimura, a senior fund manager at Mizuho Asset Management.
Underscoring those worries, Japan's economics minister warned on Tuesday that the economic damage from last month's earthquake and tsunami is likely to be worse than initially thought as power shortages will crimp factory output and disrupt supply chains. [ID:nL3E7FC092]
"There could be more negative news related to poor earnings estimates by manufacturers this fiscal year," said Kenichi Hirano, a strategist at Tachibana Securities. "If that happened,
the Nikkei could go as low as 9,300 this week."
Meanwhile, Toyota warned late on Monday that the uncertain supply of parts could threaten its output of vehicles through July, the latest sign of trouble for the global auto industry stemming from the earthquake.[ID:nN1192492]
The world's largest carmaker fell 0.6 percent to 3,240 yen after falling to an intraday low of 3,200, while other manufacturers and blue-chip exporters also slipped. Sony Corp slipped 2.9 percent to 2,502 yen.
U.S. crude oil futures extended losses by more than $2 on Tuesday on concern high fuel prices will hurt demand and as Goldman Sachs advised investors to lock in trading profits after a rally this year in many commodity markets.
U.S. crude for May delivery CLc1 hit a session low of $107.87, or down $2.05 a barrel. [ID:nL3E7FC0BD]
The Nikkei fell 1.7 percent or 164.44 points to 9,555.26. The broader Topix index dropped 1.6 percent to 838.51.
Immediate support is seen at 9,500 -- a low hit during a massive post-quake selloff a month ago.
Seiichiro Iwasawa, chief strategist at Nomura Securities, said that the Nikkei should be supported above 8,800 mid-term, the book value of the benchmark, even if more negative news hit.
Trading volumes remained thin as the market awaited U.S. corporate earnings, which may yield clues about the damage to the global supply chain and after that Japanese earnings reports in late April and early May.
Only 2.23 billion shares changed hands on the Tokyo stock exchange's main board, compared with the 2.6 billion shares traded daily on average last week.
OIL STOCKS SOLD
Shares of Tokyo Electric Power Co , the operator of the stricken Fukushima Daiichi nuclear power plant, fell 10 percent in volatile, heavy trade to 450 yen although it had climbed as high as 539 yen at one point after Vice Trade Minister Tadahiro Matsushita said he was not considering nationalisation of the company.
Some 253 million Tokyo Electric shares changed hands, the second-largest amount since the March quake and accounting for more than 10 percent of trade on the bourse's first section.
Engineers put out a fire at the plant which started after another major aftershock rocked eastern Japan, swaying buildings in central Tokyo and closing Narita airport runways.[ID:nL3E7F80U1][ID:nL3E7FB2TZ]
There has been many large aftershocks since Monday, including one on Tuesday afternoon.
"I feel the market is being undermined by a series of aftershocks that we've been experiencing recently," said Ryosuke Okazaki, chief investment officer at ITC Investment Partners Corp.
Shares of oil and gas developers Inpex Corp and Japan Petroleum Exploration Co (Japex) succumbed to profit-taking as oil extended the previous day's decline amid mounting concerns that rising fuel costs will erode demand and threaten the global economic recovery.
Inpex, Japan's biggest oil and gas developer and one of the biggest post-quake outperformers -- up 13 percent since the quake -- fell 5.2 percent to 620,000 yen. Japex lost 3.5 percent to 4,010 yen.
Analysts said that while falling commodities prices will pressure energy stocks, in the long run they will also help to ease worries over the impact of rising raw material costs on input costs and margins, providing some support to the market. (Additional reporting by Chikafumi Hodo; Editing by Edwina Gibbs)