PAHOA, Hawaii, May 13 (Reuters) - Two new fissures opened on Hawaiis Kilauea volcano , hurling bursts of rock and magma with an ear-piercing screech on Sunday, threatening nearby homes and prompting authorities to order new evacuations.

One new fissure from Sunday morning was a vivid gouge of magma with smoke pouring out both ends and was the 17th to open on the volcano since it began erupting on May 3. Some 37 buildings have been destroyed and nearly 2,000 people ordered to evacuate in the past 10 days.

Viewed from a helicopter, the crack appeared to be about 1,000 feet (300 meters) long and among the largest of those fracturing the side of Kilauea, a 4,000-foot-high volcano with a lake of lava at its summit.

It is a near-constant roar akin to a full-throttle 747 interspersed with deafening, earth-shattering explosions that hurtle 100-pound lava bombs 100 feet into the air, said Mark Clawson, 64, who lives uphill from the latest fissure and so far is defying an evacuation order.