Activity for the week of 18 July-24 July 2012
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
New Activity / Unrest
| 0.95°N, 77.87°W
| Elevation 4764 m
According to INGEOMINAS, the Observatorio de Pasto reported that during 18-24 July seismic activity at Cumbal had decreased. Variable amounts of gas emissions, mostly steam, were observed in the web camera located in Cumbal town (9 km SE) during periods of clear weather, which occurred during 20-21 July. The emissions originated from fumarolic fields located in the main crater on the NE side of Cumbal and Mundo Nuevo crater on the SW side. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").
Source: Servicio Geológico Colombiano (SGC)
| 1.22°N, 77.37°W
| Elevation 4276 m
INGEOMINAS reported that during 18-24 July earthquakes at Galeras were less than M 1.3 and located at depths not exceeding 3 km. Gas emissions, observed by a network of video cameras, contained ash almost daily. Sulfur dioxide levels fluctuated. On 18 July observatory staff working near the crater reported a strong sulfur odor and fine ash falling on the upper N flank. Ashfall was also reported to the N in the Quebrada Maragato area (municipality of Nariño). The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").
Source: Servicio Geológico Colombiano (SGC)
| Eastern Java (Indonesia)
| 8.058°S, 114.242°E
| Elevation 2769 m
CVGHM reported that, although weather conditions at Ijen often prevented views of the volcano during 1-24 July, white plumes were occasionally observed rising 50-100 m above the crater. Seismicity indicated unrest, and along with visual observations, prompted CVGHM to raise the Alert Level to 3 (on a scale of 1-4) on 24 July.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| North Island (New Zealand)
| 39.157°S, 175.632°E
| Elevation 1978 m
A sequence of small volcanic earthquakes beneath Tongariro was detected by a few of the seismometers in the permanent network. Earthquakes with magnitudes less than 2.5 were clustered between Emerald Crater (E of the summit) and the Te Mari craters (2 km E east of Ketetahi hot springs on the N flank) at 2-7 km depth. The sequence started on 13 July, soon declined, and then again increased during 18-20 July. The Alert Level was raised to 1 (on a scale of 0-5) and the Aviation Colour Code was raised to Yellow (on a four-color scale) on 20 July.
In response to the increased seismicity, GeoNet installed four portable seismographs and conducted gas and spring sampling. During 21-22 July seismicity declined; one event was detected on 23 July. Provisional analysis of the gas samples collected during 21-22 July indicated a marked increase in the volcanic gas component of the typical mix of volcanic and hydrothermal gases. Residents reported a gas odor.
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
JMA reported that during 20-23 July eight explosions from Sakura-jima's Showa Crater ejected tephra as far as 1,300 m from the crater. Incandescence from the crater was visible at night during 22-23 July. Based on information from JMA, the Tokyo VAAC reported that explosions during 18-24 July produced plumes that rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. and drifted in multiple directions. Pilots observed ash plumes on 22 and 24 July that rose to altitudes of 2.4-6.1 km (8,000-20,000 ft) a.s.l. JMA reported that an explosion on 24 July from Minami-dake Crater ejected tephra as far as 1,700 m from the crater.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Japan Meteorological Agency (JMA)
| Komba Island (Indonesia)
| 7.791°S, 123.585°E
| Elevation 633 m
Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 45 km W during 22-23 July and 110 km N and NW on 24 July.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
AVO reported that elevated surface temperatures from Cleveland were detected in satellite images during 18-20 July. Images revealed nothing unusual during 20-22 July. Cloud cover mostly prevented observations during 22-24 July; a steam plume rose from the crater on 23 July. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| 14.473°N, 90.88°W
| Elevation 3763 m
INSIVUMEH reported that during 20-24 July explosions from Fuego produced ash plumes that rose 200-400 m above the crater and drifted W and NW. Fumarolic plumes drifted the same direction. Glow radiated 100-150 m above the crater. Lava flows traveled 200-250 m down the Taniluyá (SW) drainage; detached blocks from the lava-flow fronts produced incandescent avalanches.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
KVERT reported mostly weak seismic activity from Karymsky during 13-23 July. Satellite imagery showed a weak thermal anomaly on the volcano during 13-19 July. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 18-24 July HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Measurements indicated that the gas plume from the vent continued to deposit variable amounts of spatter and Pele's hair onto nearby areas. The lava pond in a small pit on the E edge of the Pu'u 'O'o crater floor and two vents along the S edge of the floor were visible with the web cameras. Lava flows were active on the pali and the coastal plain; the active lava-flow front was about 1.9 km from the ocean on 24 July.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Nevado del Ruiz
| 4.892°N, 75.324°W
| Elevation 5279 m
According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that during 22-24 July low levels of tremor were detected at Nevado del Ruiz, possibly associated with continuing gas and ash emissions. Satellite imagery and ground-based observations on 22 July showed high levels of sulfur dioxide emissions. The Alert Level remained at II (Orange; "eruption likely within days or weeks").
Source: Servicio Geológico Colombiano (SGC)
| 19.023°N, 98.622°W
| Elevation 5393 m
CENAPRED reported that during 18-23 July seismicity at Popocatépetl indicated continuing gas-and-ash emissions; cloud cover prevented observations during most of this period. Incandescence from the crater was periodically observed and sometimes increased with accompanying emissions. A steam-and-gas plume rose from the crater on 19 and 24 July, and ash-and-gas plumes were observed on 20 and 22 July. Activity increased for a period during 20-21 July; incandescent tephra was ejected 500 m above the crater and ashfall was reported in Ozumba (18 km W). The Alert Level remained at Yellow, Phase Three.
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)
| 2.005°S, 78.341°W
| Elevation 5286 m
According to the Washington VAAC, a pilot reported that a possible eruption from Sangay occurred prior to 1438 on 20 July. Ash was not observed in satellite imagery and a SIGMET issued for the event was later cancelled.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that during 13-21 July explosive activity at Shiveluch continued. Observers noted gas-and-steam activity during 12-13, 15-18, 21, and 23 July; weather conditions prevented observations of the volcano on the other days. Satellite imagery showed a thermal anomaly on the lava dome during 13-20 July. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that during 13-20 July activity at the Soufrière Hills lava dome was at a low level. Heavy rain on the morning of 19 July generated lahars in several valleys on the W flank of the volcano. Lahars in the Belham valley (NW) were small and restricted to the upper reaches of the valley. The Hazard Level remained at 2 (on a scale of 1-5).
Source: Montserrat Volcano Observatory (MVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
IG reported that during 18-24 July visual observations of Tungurahua were limited due to cloud cover. On 20 July a steam plume drifted W, and on 21 July a steam plume rose 200 m above the crater and drifted the same direction. Many of the drainages contained muddy waters through the reporting period; a lahar descended the Mapayacu drainage (SW) on 23 July.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Criteria & Disclaimers
The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:
- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.
Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.
It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.
1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are monthly, and more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.
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