As yet another giant crack opens in the ground, 20 fissures have now erupted on the Big Island in the past week and a half.  This one was explosive-sending lava bombs, or chunks of molten rock, shooting hundreds of feet in the air.

Air quality is still a major concern with sulfur dioxide spewing from the lava, and smaller cracks that keep appearing. The National Guard is going through neighborhoods monitoring the levels.

Even from 25 miles away, once can see the ash plumes from the summit of Kilauea billowing into the sky.  It's even visible from the international space station.  Some of the ash is falling in nearby towns.

Geologists warn to watch for, what they say, could be a giant explosion from this crater any day-that could send more ash raining down for miles. 

The threats are having a big impact on tourism. Officials say bookings on the Big Island are down 50 percent.  Norwegian Cruise Lines canceled its stops this week in Kona on the far side of the island.  In Hilo, which is more than 20 miles from the volcanic activity, business owners call it an overreaction. As officials stress, these other parts of the island are safe and open for business.