Anatahan Volcano
Anatahan volcano forms the small 9 x 3.7 E-W elongated Anatahan Island in the northern Marianas, about 120 km north of Saipan, the regional Commonwealth of the Northern Mariana Islands capital.
The volcano is at the southern end of the 1500 km long chain of volcanoes formed by the Izu-Bonin-Mariana subduction-zone volcanic arc.
The island is only a tiny fraction (about 1%) of the volcano's entire volume, which rises 3700 m from the sea floor and has a basal diameter of 35 km. It is topped by a 5x2.3 km wide E-W elongated summit caldera. Its principal crater is a 1.4x1.2 km wide and 200 m deep pit crater in the eastern part of the caldera. The highest point of the island is on the western rim.
The first known volcanic activity occurred in 2003, when the volcano came back to life, and has been in a state of frequent eruptions since then.
Anatahan volcano eruptions: 2007-08, 2006, 2004-05, 2003
Latest nearby earthquakes
| Date and Time | Mag / Depth | Distance / Location | |||
|---|---|---|---|---|---|
Background
The caldera consists of an older western and younger eastern part. Ponded lava flows and pyroclastic deposits fill the floor of the western caldera, whose SW side is cut by a fresh-looking smaller crater.The 2-km-wide eastern portion of the caldera contained a steep-walled inner crater whose floor prior to the 2003 eruption was only 68 m above sea level. A submarine volcano, named NE Anatahan, rises to within 460 m of the sea surface on the NE flank of the volcano, and numerous other submarine vents are found on the NE-to-SE flanks.
Sparseness of vegetation on the most recent lava flows on Anatahan had indicated that they were of Holocene age, but the first historical eruption of Anatahan did not occur until May 2003, when a large explosive eruption took place forming a new crater inside the eastern caldera. (Smithsonian / GVP)
Significant volcanic eruptions: Anatahan volcano
| Date | Note | VEI | Deaths | Damage | |
|---|---|---|---|---|---|
Historical obs./docs. | 2 | ||||
| East Crater Historical obs./docs. | 2 | ||||
| East Crater Historical obs./docs. | 3? | ||||
| East Crater Historical obs./docs. | 3 | ||||
Anatahan Volcano FAQ
+When was the last eruption of Anatahan volcano?
The last confirmed eruption of Anatahan occurred during 2007 - 2008.
+How often does Anatahan volcano erupt?
There are no known historic eruptions, but evidence from geologic records shows that it has had at least 4 eruptions over the past 10,000 years. This number is likely much higher because many past eruptions might not have left evidence recognizeable today and/or the volcano might not have been studied in too much detail. Using the available data, a very conservative estimate is that Anatahan volcano erupts every 2,500 years.
+How active is Anatahan volcano at present?
Anatahan volcano is occasionally active: Since 1900, it has had 6 eruptions, and been active during 6 years out of 126 as of now. This means, Anatahan has been in eruption one in 21 years on average. The last eruption was from 2007 until 2008 and ended 17 years ago.
+When was the largest eruption of Anatahan volcano?
The largest eruption of Anatahan volcano in historic times occurred during 2004 - 2005. It ranks as a "vulcanian" eruption with a magnitude 3 on the VEI (Volcanic Explosivity Index) scale.
Latest satellite images
Anatahan Volcano Maps
