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Marchena

Photo of this volcano
  • Country
  • Volcanic Region
  • Landform | Volc Type
  • Last Known Eruption
  • 0.33°N
  • 90.47°W

  • 343 m
    1,125 ft

  • 353080
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number


Most Recent Bulletin Report: October 1991 (BGVN 16:10) Citation IconCite this Report

Flow front advances into sea with no explosive venting

[The eruption] has continued without explosive venting visible from a distance. Observers on a boat that passed Marchena on 7 or 8 November reported vigorous steaming at the W coast. Water near the flow front was too hot to touch and numerous fumaroles were evident inland. Since David Day's 28-30 September visit, lava had formed a single broad front at the coast, closing the small bay where Day had landed.

Reports collected by Day provided additional information about the timing and characteristics of the early phases of the eruption. The first reported activity was a "suspicious" large cloud seen over Marchena on 25 September at 1840 from ~65 km S (at Bartolomé). An explosion was observed at 1905 from ~90 km SSE (Turtle Cove, Santa Cruz Island). A low white cloud near the coast was seen with infrared binoculars at about 2100. Witnesses at three sites ~65 km S reported 7-8 evenly spaced vents that remained active throughout the night. Incandescent ejecta appeared to rise roughly the equivalent of the island's elevation (~350 m), with height increases of ~25% during the strongest activity. A more vigorous vent, lying W of the others, was first seen at about 0300 on 26 September. Ejecta heights from the W vent appeared to exceed those from the other vents by ~50%.

Information Contacts: D. Day, Isla Santa Cruz.

The Global Volcanism Program has no Weekly Reports available for Marchena.

Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

08/1991 (BGVN 16:08) First historical eruption

09/1991 (BGVN 16:09) Lava from circumferential fissure flows into caldera and ocean

10/1991 (BGVN 16:10) Flow front advances into sea with no explosive venting




Information is preliminary and subject to change. All times are local (unless otherwise noted)


August 1991 (BGVN 16:08) Citation IconCite this Report

First historical eruption

Marchena . . . started erupting on 25 September. The TOMS instrument aboard the Nimbus-7 satellite passed at about 1100 and sensed no SO2, but the next pass, at the same time on 26 September, mapped a 300-km plume to the SW with an SO2 content estimated to be close to 100 kt. High SO2 values immediately over the volcano indicated that the eruption was still vigorous at that time. On the following day the plume was nearly twice as long, but had almost vanished by the same time on 28 September. Weather satellite images during this period showed low cloud cover, but no conclusive indication of the volcanic plume. . . .

Information Contacts: A. Carrasco, Charles Darwin Research Station; S. Doiron, GSFC; SAB.


September 1991 (BGVN 16:09) Citation IconCite this Report

Lava from circumferential fissure flows into caldera and ocean

The eruption was first observed on 25 September at about 2100 from a ship ~ 75 km S of Marchena [but see 16:10], and glow remained visible through the night. A large black and white eruption cloud was reported the next day, but no glow was evident during cloudy weather that night from a nearby island. During an overflight around midday on 27 September, a dark plume was visible above low weather clouds.

When David Day and others arrived at the island's W coast on 28 September at about 2230, lava was flowing into the sea along a front ~1.5 km wide. Incandescence was evident at about 10 sites over a roughly 3 x 3 km area, but lava fountaining had apparently stopped. The next day, small quantities of Pele's hair were found on the beach near the fresh flows, along with substantial numbers of dead fish and other marine organisms. Scuba divers found glassy breccia near the shore, a zone of aa rubble extending seaward for several hundred meters, and, with gradual increase in slope from 25 to 35 m depth, a small lava flow that included pillow structures. A 30 September summit climb revealed new lava covering much of the caldera's SW floor, suggesting that a circumferential fissure several kilometers long had been active on the W to SW rim, supplying lava to both the caldera floor and the outer flank.

Information Contacts: D. Day, Isla Santa Cruz.


October 1991 (BGVN 16:10) Citation IconCite this Report

Flow front advances into sea with no explosive venting

[The eruption] has continued without explosive venting visible from a distance. Observers on a boat that passed Marchena on 7 or 8 November reported vigorous steaming at the W coast. Water near the flow front was too hot to touch and numerous fumaroles were evident inland. Since David Day's 28-30 September visit, lava had formed a single broad front at the coast, closing the small bay where Day had landed.

Reports collected by Day provided additional information about the timing and characteristics of the early phases of the eruption. The first reported activity was a "suspicious" large cloud seen over Marchena on 25 September at 1840 from ~65 km S (at Bartolomé). An explosion was observed at 1905 from ~90 km SSE (Turtle Cove, Santa Cruz Island). A low white cloud near the coast was seen with infrared binoculars at about 2100. Witnesses at three sites ~65 km S reported 7-8 evenly spaced vents that remained active throughout the night. Incandescent ejecta appeared to rise roughly the equivalent of the island's elevation (~350 m), with height increases of ~25% during the strongest activity. A more vigorous vent, lying W of the others, was first seen at about 0300 on 26 September. Ejecta heights from the W vent appeared to exceed those from the other vents by ~50%.

Information Contacts: D. Day, Isla Santa Cruz.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 1 confirmed Holocene eruptive periods.

1991 Sep 25 - 1991 Nov 16 (?) ± 15 days Confirmed Eruption VEI: 2

Episode 1 | Eruption West to SW caldera rim
1991 Sep 25 - 1991 Nov 16 (?) ± 15 days Evidence from Observations: Reported

List of 5 Events for Episode 1 at West to SW caldera rim

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava fountains
   - - - -    - - - - Lava flow
   - - - -    - - - - Lava flow Entered water.
1991 Sep 25    - - - - VEI (Explosivity Index)
Deformation History

There is no Deformation History data available for Marchena.

Emission History

There is data available for 1 emission periods. Expand each entry for additional details.


Emissions during 1991 Sep 26 - 1991 Sep 26 [200 kt SO2 at 2 km altitude]

Start Date: 1991 Sep 26 Stop Date: 1991 Sep 26 Method: Satellite (Nimbus-7 TOMS)
SO2 Altitude Min: 2 km SO2 Altitude Max: 2 km Total SO2 Mass: 200 kt

Data Details

Date Start Date End Assumed SO2 Altitude SO2 Algorithm SO2 Mass
19910926 2.0 200.000
GVP Map Holdings

The Global Volcanism Program has no maps available for Marchena.

Smithsonian Sample Collections Database

The following 57 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 118120-1 Basalt -- 31 Jul 1970
NMNH 118120-10 Basalt -- 31 Jul 1970
NMNH 118120-11 Basalt -- 1 Aug 1970
NMNH 118120-12 Basalt -- 1 Aug 1970
NMNH 118120-13 Tuff -- 1 Aug 1970
NMNH 118120-14 Tuff -- 1 Aug 1970
NMNH 118120-15 Flow Rock -- 1 Aug 1970
NMNH 118120-16 Tuff -- 1 Aug 1970
NMNH 118120-17 Volcanic Rock -- 1 Aug 1970
NMNH 118120-18 Volcanic Rock -- 1 Aug 1970
NMNH 118120-19 Flow Rock -- 2 Aug 1970
NMNH 118120-2 Basalt -- 31 Jul 1970
NMNH 118120-20 Basalt -- 2 Aug 1970
NMNH 118120-21 Volcanic Rock -- 2 Aug 1970
NMNH 118120-22 Calcareous Sinter -- 2 Aug 1970
NMNH 118120-23 Tuff -- 2 Aug 1970
NMNH 118120-24 Lava -- 2 Aug 1970
NMNH 118120-25 Lava -- --
NMNH 118120-26 Tuff -- 2 Aug 1970
NMNH 118120-27 Plagioclase Basalt -- 2 Aug 1970
NMNH 118120-28 Basalt -- 2 Aug 1970
NMNH 118120-29 Basalt-Andesite -- 2 Aug 1970
NMNH 118120-3 Basaltic Spatter -- 31 Jul 1970
NMNH 118120-30 Plagioclase Basalt -- 2 Aug 1970
NMNH 118120-31 Picrite -- 2 Aug 1970
NMNH 118120-32 Basalt -- 2 Aug 1970
NMNH 118120-33 Basalt -- 2 Aug 1970
NMNH 118120-34 Basalt -- 2 Aug 1970
NMNH 118120-35 Basalt -- 2 Aug 1970
NMNH 118120-36 Igneous Rock -- --
NMNH 118120-37 Igneous Rock -- --
NMNH 118120-38 Igneous Rock -- --
NMNH 118120-39 Volcanic Rubble -- 17 Jun 1971
NMNH 118120-4 Tuff -- 31 Jul 1970
NMNH 118120-40 Volcanic Rubble -- 17 Jun 1971
NMNH 118120-41 Volcanic Rubble -- 17 Jun 1971
NMNH 118120-42 Tephra -- 17 Jun 1971
NMNH 118120-43 Tuff -- 17 Jun 1971
NMNH 118120-44 Volcanic Rubble -- 17 Jun 1971
NMNH 118120-45 Volcanic Ash -- 17 Jun 1971
NMNH 118120-46 Volcanic Ash -- 17 Jun 1971
NMNH 118120-47 Volcanic Cinder -- 17 Jun 1971
NMNH 118120-48 Tephra -- 17 Jun 1971
NMNH 118120-49 Tephra -- 18 Jun 1970
NMNH 118120-5 Basalt -- 31 Jul 1970
NMNH 118120-50 Tephra -- 18 Jun 1970
NMNH 118120-51 Tephra -- 18 Jun 1970
NMNH 118120-52 Basalt -- 18 Jun 1970
NMNH 118120-53 Tuff -- 18 Jun 1970
NMNH 118120-54 Tephra -- 18 Jun 1970
NMNH 118120-55 Tephra -- 18 Jun 1970
NMNH 118120-56 Scoria -- 18 Jun 1970
NMNH 118120-57 Accretionary Lapilli -- 17 Jun 1971
NMNH 118120-6 Dacite -- 31 Jul 1970
NMNH 118120-7 Volcanic Rock -- 31 Jul 1970
NMNH 118120-8 Volcanic Rock -- 31 Jul 1970
NMNH 118120-9 Volcanic Rock -- 31 Jul 1970
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