1. Active Volcanoes of the World

2. Nyamuragira ( Congo )

3. What is a volcanic eruption?  The arrival of volcanic products at the surface of the Earth or other planetary bodies is termed an eruption. Some definitions of the word include purely gaseous expulsions, but we confine the term to events that involve the explosive ejection of fragmental material, the effusion of liquid lava, or both. Other definitions restrict eruptions to magmatic events, but the fragmental material ejected may be old as well as new.

4. Whakaari ( New Zealand )

5. How many active volcanoes are known? Erupting now:perhaps 20 Each year:50-70 Each decade:about 160 Historical eruptions: about 550 Known Holocene eruptions (last 10,000 years): about 1300 Known (and possible) Holocene eruptions: about 1500 Erupting now:perhaps 20 Each year:50-70 Each decade:about 160 Historical eruptions: about 550 Known Holocene eruptions (last 10,000 years): about 1300 Known (and possible) Holocene eruptions: about 1500

6. Soufriere ( Caribbean Island )

7. How long does an eruption last?  Clearly some eruptions last for a very long time, like Stromboli's At the turn of the century the following 15 volcanoes have been erupting more or less continuously through the last three decades and are likely to remain active for some time:  Stromboli and Etna (Italy); Erta Ale (Ethiopia); Manam, Langila, and Bagana (Papua New Guinea); Yasur (Vanuatu); Semeru and Dukono (Indonesia); Sakura-jima (Japan); Santa Maria and Pacaya (Guatemala); Arenal (Costa Rica); Sangay (Ecuador); and Erebus (Antarctica). However, other eruptions end swiftly: 10% of those for which we have accurate durations lasted no longer than a single day, most end in less than 3 months, and few last longer than 3 years. The median duration is about 7 weeks.

8. Mount Etna ( Italy )

9. Has volcanic activity has been increasing?  A look at the number of volcanoes active per year, over the last few centuries, shows a dramatic increase, but one that is closely related to increases in the world's human population and communication.

10. How do scientists forecast volcanic eruptions?  Scientists use a wide variety of techniques to monitor volcanoes, including seismographic detection of the earthquakes and tremor that almost always precede eruptions, precise measurements of ground deformation that often accompanies the rise of magma, changes in volcanic gas emissions, and changes in gravity and magnetic fields. Although not diagnostic individually, these techniques, when used in combination at well-monitored volcanoes, have resulted in successful predictions. At Pinatubo volcano (Philippines) in 1991, a successful forecast saved thousands of lives

11. Kilauea ( Hawaiian Islands )

12. Most Active Volcanoes in the world  Many volcanoes have been in continuous eruption for decades.  Etna, Stromboli, and Yasur have been erupting for hundreds or thousands of years.

13. Mayon ( Philippines )

14. Most Active Volcanoes in the world  The following 4 volcanoes emit the most lava. Kilauea (Hawaii), Mt Etna (Italy), Piton de la Fournaise (Réunion), Nyamuragira, (D.R. Congo)

15. The Chaiten ( Chile )

16. Most Active Volcanoes in the world Volcano NameLocationContinuous Eruptions EtnaItaly3500 years StromboliItaly2000 years YasurVanuatu800 years AmbrymVanuatu1935- TinakulaSolomon Islands1951?- Erta AleEthiopia1967- ManamPapua New Guinea1974- LangilaPapua New Guinea1960- BaganaPapua New Guinea1972- SemeruIndonesia1967- MerapiIndonesia1967- DukonoIndonesia1933- Sakura-jimaJapan1955- Suwanose-jimaJapan1949- Santa MariaGuatemala1922- PacayaGuatemala1965- ArenalCosta Rica1968- SangayEcuador1934- ErebusAntarctica1972- Piton de la FournaiseReunion1920- KilaueaHawaii1983-

17. Popocatepetl ( Mexico )

18. Sakurajima ( Japan )