Activity for the week of 17 November-23 November 2004
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
| 1.22°N, 77.37°W
| Elevation 4276 m
Galeras volcano erupted explosively on 21 November at 1544, Instituto Colombiano de Geología y Minería reported. The eruption produced a shock wave felt as far away as Cimarrones (18 km N of the volcano), Chachagui (17 km N of the volcano), and Laguna de La Cocha (20 km SW of the volcano). Effects of the shock wave varied from a loud roar, to the vibration of large windows, to the feeling of an earthquake. Ballistic rock blocks were expelled and fell nearly 3 km from the volcano on its eastern flank, producing short-lived forest fires. The eruption produced an ash-and-gas column that rose to an estimated height of 9-10 km a.s.l and drifted to the S and W. The Washington VAAC reported that satellite imagery through 2015 on 21 November revealed that high level ash estimated to be near 9 km a.s.l had moved to the W, while low level ash estimated to be near 4-5 km a.s.l remained in the vicinity of the summit of the volcano and showed little motion.
Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)
| Papua New Guinea
| 4.08°S, 145.037°E
| Elevation 1807 m
During 17-23 November, the Darwin VAAC issued numerous volcanic ash advisories concerning plumes emitted from Manam that were visible on satellite imagery. On 19 November at 1125, a plume visible on satellite imagery reached a height of 7-8 km a.s.l and extended 74 km to the NE. A plume detected on 23 November at 2225 rose to around 14 km a.s.l and extended 130 km to the ESE. The Aviation Color Code was at Red, the highest level. Rabaul Volcanological Observatory advised that the eruptions of Manam are continuing with occasional stronger activity.
Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Rabaul Volcano Observatory (RVO)
| 19.514°N, 103.62°W
| Elevation 3850 m
During 16-22 November, block-lava flows continued to travel down Colima's N, W, NW, and S flanks as they have since 30 September. The lava flow on the N flank is 2200 m long and approximately 330 m wide. The lava flow advancing on the NW flank is at least 600 m long by 200 m at its widest part. Several small explosions occurred daily.
Source: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima
| 14.473°N, 90.88°W
| Elevation 3763 m
During the report period, avalanches of incandescent volcanic material continued towards the Lajas and Taniluyá ravines on the volcano's SE and SW flanks. Small and moderate explosions expelled abundant incandescent lava to heights ~150 m above the crater. Some explosions generated rumblings, shock waves, and fine ash that was deposited on the skirts of the volcano. Near the end of the report period, the energy level of the eruption lowered, especially the flow of lava towards the Lajas ravine.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Lava from Kilauea's PKK flow continued to enter the sea at the newly formed lava delta at eastern Lae`apuki delta during 17-23 November. Fieldwork on 18 November determined that the new lava delta is 260 m long and extends about 80 m beyond pre-existing land (the front of the old Lae`apuki delta). The area of the delta is about 1.2 ha. One entry point was on the far west end of the delta, but most of the activity was east of center. During 17-23 November, all vents in the crater of Pu`u `O`o were incandescent. Seismicity at Kilauea's summit increased during the report period, with numerous small long-period earthquakes coming from the southern and southeastern parts of the caldera. Tremor remained low to absent, however. The tremor at Pu`u `O`o remained at moderate strength. No significant deformation occurred.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| DR Congo
| 1.52°S, 29.25°E
| Elevation 3470 m
The Toulouse VAAC reported that an eruption began at Nyiragongo sometime earlier than 0700 on 22 November. A narrow SW-drifting plume was discernable on satellite imagery at a height of around 5 km a.s.l. A narrow plume was visible again on satellite imagery on 23 November at 1130, although no ash was identifiable.
Source: Toulouse Volcanic Ash Advisory Centre (VAAC)
| North Island (New Zealand)
| 39.28°S, 175.57°E
| Elevation 2797 m
IGNS reported that a new heating cycle may be under way at Ruapehu volcano. The temperature of Crater Lake has increased three degrees to 18 degrees Celsius, and elevated levels of volcanic tremor have occurred over the last three weeks. Ruapehu remained at Volcanic Alert Level 1 (some signs of volcano unrest).
| 14.757°N, 91.552°W
| Elevation 3745 m
During 17-22 November, weak-to-moderate explosions occurred at Santa María's Santiaguito lava-dome complex, causing the emission of ash columns to heights of 300-1000 m above the active crater. Slight amounts of light gray ash fell on the flanks of the volcano.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
Seismicity was above background levels at Shiveluch during 12-19 November, with weak shallow earthquakes occurring at a depth of 0.5 km beneath the active lava dome. Based on interpretations of seismic data, possible ash-and-gas explosions up to 6 km a.s.l were registered on 15 November. Ash-and-gas explosions up to 4-5 km a.s.l were noted all week and possible weak ash-and-gas explosions and hot avalanches also occurred. According to visual and video data, ash-and-gas explosions rose up to 4-5 km a.s.l on 11 and 18 November. Gas-and-steam plumes were observed on 11 and 15 November. Shiveluch remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| United States
| 61.299°N, 152.251°W
| Elevation 3374 m
Elevated levels of seismicity continued to be recorded at Mount Spurr. Seismicity rates have been relatively constant in the last week at roughly 5 locatable earthquakes per day. No unusual activity was observed in satellite or web camera images. Spurr remained at Concern Color Code Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
Growth of the new lava dome inside the crater of St. Helens continued and was accompanied by intermittent emissions of steam and ash. When weather permitted during the report period, a plume was observed rising passively and drifting out of the crater. The plume occasionally contained minor ash, which fell out in the crater and on the flanks of the volcano, darkening the snow.
Seismicity remained at low levels compared to that observed early in this unrest. The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor and feeding the extrusion of lava onto the surface, where it builds a dome. The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor, thereby reducing the probability of highly explosive eruptions in the near term.
A new GPS site installed 20 November near the top of the new lava dome showed that the highest point on the new lava dome is at an altitude of 2256 m a.s.l, or about 76 m higher than the summit of the 1980-86 lava dome. In its first 24 hours near the top of the new lava dome, this GPS site moved about 10 m to the SE and 2 m vertically, confirming visual and photographic observations that the new lava dome is moving at an impressive rate.
Gas measurements taken on 20 November show that daily gas emissions remain at a more or less constant rate of around 180 metric tons of sulfur dioxide, about 900 metric tons of carbon dioxide, and several metric tons of hydrogen sulfide.
St. Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
Volcanic and seismic activity at Tungurahua during the report period were at relatively low levels, characterized by several long-period earthquakes and small to moderate explosions. Emissions mainly consisted of steam, gas, and small amounts of ash. During 17-18 November, explosions generated steam columns that rose 300-500 m above the summit of the volcano and drifted SSW.
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.
2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.
3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.
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