Restless volcanoes from around the world spew ash, steam, and concern in their wake.

© Oliver Bluett, AFP/GettyMount Tavurvur erupts in eastern Papua New Guinea on Friday.
The Mount Tavurvur volcano in eastern Papua New Guinea jolted awake early Friday morning, belching rocks, ash, and steam (see above) nearly 60,000 feet (18,288 meters) into the air.

Local residents evacuated their homes on Friday, and Qantas Airways modified flight paths for planes heading to Tokyo and Shanghai from Sydney, Australia, according to news reports. (Watch video: "Volcano 101.")

The last time Mount Tavurvur erupted, in 1994 - at the same time as nearby Mount Vulcan - both volcanoes destroyed the town of Rabaul in Papua New Guinea.

Fire and ice

© Marco Nescher, Reuters
The Bárđarbunga volcano in Iceland gave officials a scare late last week when it started rumbling to life, as seen on August 29.

The volcano lies under Europe's largest ice cap, Vatnajökull, and government officials worried that an eruption would cause havoc on the ground and in the air.Those fears didn't materialize, and Iceland officials downgraded air travel warnings on Sunday.

Bárđarbunga may have settled, but don't count it out. Steam and smoke still leak through fissures in a lava field just north of the Vatnajökull glacier, as seen above. (See "Q&A: Why Iceland's Volcanoes Have Vexed Humans for Centuries.")

Rock and Roll

© Jose Jacome, EPA
The Tungurahua volcano in central Ecuador (pictured on August 28) has been rocking the nearby town of Baños (map) since August 21 with tremors, explosions, and earthquakes.

The explosions can sound like cannon blasts, roars, and gunfire, according to the Smithsonian's Global Volcanism Program.

Night light

© Himawan Listya N, Xinhua/ZUMA Wire
Mount Slamet in central Java, Indonesia, puts on a show August 23 as it sends streamers of lava into the night sky.

Volcanic activity on the mountain increased in the beginning of August, prompting government officials to ban climbing activities on the mountain.