* Bahrain links pipeline explosion to Iran, Saudis may act
* Saudi state-linked funds continue support operation
* But trading volume lowest since corruption crisis began
* Dar Al Arkan continues surge after earnings
* Dubai's Emaar rises before earnings
By Andrew Torchia
DUBAI, Nov 12 (Reuters) - Gulf stock markets mostly fell on Sunday because of rising geopolitical tensions and jitters related to Saudi Arabia's anti-corruption investigation, although trading volume in Riyadh shrank, suggesting there was less panic selling of shares.
Geopolitical worries increased at the weekend after Bahrain linked an explosion at its main oil pipeline on Friday to Iran. There is now considerable concern about the possibility of aggressive Saudi action against Iranian interests in the region.
Meanwhile, wealthy Saudi individuals have been selling stocks in Riyadh and around the region - some of them hoping to move money out of the Gulf - since the anti-graft investigation was revealed at the start of last week.
The Saudi index fell as much as 1.5 percent during the day but closed only 0.3 percent lower after state-linked funds once again bought stocks in late trade, a deliberate operation to support the market and prevent a crash, asset managers said. National Commercial Bank, a key stock held by the Public Investment Fund, rose 1.3 percent.
But total volume, while active, was at its lowest level since the investigation was announced, suggesting the funds were no longer having to work as hard to support the market.
Among stocks linked to people who have been detained in the probe, Kingdom Holding rebounded 5.8 percent, although it remained 16 percent below its level before chairman Prince Alwaleed bin Talal was arrested.
Al Tayyar Travel, whose founder was detained, sank a further 5.0 percent in heavy trade, bringing its losses to 24 percent.
Real estate developer Dar Al Arkan surged 7.0 percent and was the most heavily traded stock. On Thursday, it had jumped its 10 percent daily limit after reporting third-quarter net profit almost doubled from a year ago to 209.6 million riyals ($55.9 million), as sales more than doubled.
MedGulf rose 2.2 percent after reporting a flat third-quarter profit before zakat; for the second quarter, it had posted a net loss that widened from a year earlier.
Dubai's index climbed 0.4 percent. Falling stocks outnumbered rising ones by 17 to 13, but Emaar Properties added 1.0 percent before it reported quarterly earnings.
After the close, Emaar posted a 32 percent rise in third-quarter net profit to 1.51 billion dirhams ($411.2 million), beating SICO Bahrain's forecast of 1.36 billion dirhams.
Amusement park operator DXB Entertainments fell 2.6 percent after reporting its third-quarter loss more than doubled from a year earlier to 284.1 million dirhams ($77.4 million).
Qatar's index edged down 0.1 percent as Qatar National Cement tumbled 5.9 percent to 58.23 riyals, its lowest level since 2010, falling below technical support at 60 riyals, which had been tested and held since June.
* The index fell 0.3 percent to 6,933 points.
* The index rose 0.4 percent to 3,465 points.
* The index edged down 0.1 percent to 4,374 points.
* The index edged down 0.1 percent to 7,876 points.
* The index fell 0.6 percent to 14,271 points.
* The index dropped 1.3 percent to 6,176 points.
* The index fell 0.3 percent to 1,264 points.
* The index added 0.2 percent to 5,067 points. (Editing by Larry King)