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Web resource for posting and exchange of Infrasound produced by Volcanoes





REVENTADOR (Infrasound Examples | Photo Gallery)

Latitude: 0.077°S 0°4'39"S
Longitude: 77.656°W 77°39'21"W


Reventador volcano is the most historically active stratovolcano in Ecuador�s easternmost volcanic arc with at least 17 important eruptions reported in historic times.  The active cone, which is currently about 3500 m above sea level, is growing in the center of a ~4 km wide caldera formed by sector collapse that occurred 20 ka bp [Inecel, 1988].  During the 20th century, primary eruptive intervals have occurred in 1898-1912, 1926-1929, 1944, 1958-1960, 1972, 1973-1974, 1976, 2002-2003, and 2004-2005 [Hantke and Parodi, 1966].  On November 3, 2002 a VEI magnitude IV eruption from Reventador marked the largest eruption in Ecuador in more than a century.  A large 200-m deep crater / chasm was incised into the cone and combined debris and pyroclastic flows extended more than 9 km from the vent.  Subsequent andesitic lava flows were erupted from the central vent and from a flank vent on the cone.  Renewed andesitic lava flows were erupted in 2004 and 2005 and small-scale explosive activity began in June 2005 and tapered in the latter part of 2005.

A small antennae of microphones were deployed at Reventador in June 2005 to differentiate between eruption-associated tremor and deeper tremor.  In July 2005 the infrasonic monitoring was focused at three sites ranging radially away from the vent at distances of 1.7 to 7 km.  This distributed network has been used to differentiate between volcanic and non-volcanic sources [Johnson et al., 2006].

File Link Description of File Description of Event Source
Reventador_videotrace01.gif 2.6 Mbyte Forty minute record (at 5 minutes per s) from 8-23-05 at 5:00 AM (local time).  Video starts before dawn and extends into daylight hours.  Acoustic and seismic data from station RVEN (~1700 m from vent) are shown.  Field of view (top-to-bottom) of image frame is ~4 km. Long-duration eruptive sequence (~30 minutes) with several distinct pulses that are reflected seismically, acoustically, and in the video frames.  Maximum infrasonic peak-to-peak pressure is 7 Pa. Johnson, J.B., Lees, J., Yepes, H., U. of New Hampshire, U. of North Carolina, Instituto Geofisico of the Escuela Politecnica Nacional (Quito), U. of New Hampshire.  Examples collected and analyzed in August and September 2005.  Contact Jeff Johnson or Jonathan Lees for more information
Reventador_videotrace02.gif 1.0 Mbyte Ten minute record (at 5 minutes per s) from 8-24-05 at 6:00 AM (local time).  Acoustic and seismic data from station RVEN (~1700 m from vent) are shown.  Field of view (top-to-bottom) of image frame is ~4 km. Relative shor (~2 minutes) pyroclastic-laden eruption column extending about 1 km above the vent..  Maximum infrasonic peak-to-peak pressure is 2 Pa.
Reventador_videotrace03.gif 5.4 Mbyte Sixty minute record (at 5 minutes per s) from 8-24-05 at 4:00 PM (local time).  Acoustic and seismic data from station RVEN (~1700 m from vent) are shown.  Field of view (top-to-bottom) of image frame is ~4 km. Active plume degassing associated with energetic seismic and acoustic tremor.  Tremor endures beyond the 60-minute example window.  Maximum peak-to-peak infrasonic pressure is 6 Pa at the onset of the event.
Reventador_videotrace04.gif 3.7 Mbyte Sixty minute record (at 5 minutes per s) from 8-5-05 at 9:00 AM (local time).  Acoustic and seismic data from station RVEN (~1700 m from vent) are shown.  Field of view (top-to-bottom) of image frame is ~4 km. Sequence of two pyroclastic-laden explosions occurring more than 15 minutes apart.  Both events are followed by high amplitude seismo-acoustic tremor that is associate with some generalized degassing.  Maximum peak-to-peak infrasound pressure is 5 Pa at the onset of the first event.
Reventador_videotrace05.gif 4.5 Mybte Sixty minute record (at 5 minutes per s) from 8-6-05 at 5:00 AM (local time).  Video starts before dawn and extends into daylight hours.  Acoustic and seismic data from station RVEN (~1700 m from vent) are shown.  Field of view (top-to-bottom) of image frame is ~4 km. Sequence of two pyroclastic-laden explosions occurring ~20 minutes apart.  The first event has a very short duration (< 1 minute) infrasonic transient and the second exhibits an extended duration (> 5 minute) coda.  Maximum peak-to-peak infrasound pressure is 7 Pa at the onset of the second event.

 

View of Reventador Caldera from the east (Ramon, 2005) Active 2004 lava flow (Johnson, 2004) Still-active lava flows from November 2004 (Ramon, 2004)
View down into lava pad forming in November 2004 (Johnson, 2004) Night-time view down into crater (Johnson, 2004) Small explosion occurring in September 2005 (Johnson, 2005)
Paroxysmal explosion occurring at 9:00 PM (local time) on September 12, 2005 (Johnson, 2005) Typical passive degassing from active cone (Johnson, 2004) View of cone and 2002-03 lava flows (Johnson, 2004)