Activity for the week of 30 June-6 July 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
| Flores Island (Indonesia)
| 8.676°S, 122.455°E
| Elevation 1661 m
According to news articles, increased volcanic activity began at Egon on 3 July. Ash from an explosion on the night of the 3rd drifted as far W as Maumere, the capital of Flores. About 2,000 residents near the volcano were evacuated. The four villages worst affected were Egon Gahar, Natakoli, Hale, and Hebing. According to DVGHM, two small explosions occurred at Egon, producing ash clouds to heights of ~150 m. Egon was listed at Alert Level 2 (on a scale of 1-4).
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), The Jakarta Post
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
On 2 July an explosion at Sakura-jima produced a S-drifting ash cloud to a height of ~1.5 km a.s.l. Another explosion later that day produced an ash cloud to an unknown height.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Mariana Islands (USA)
| 16.35°N, 145.67°E
| Elevation 790 m
On 2 July, the seismicity level at Anatahan rose nearly as high as it was in late April 2004. After the 2nd, seismicity declined slightly. The nature of the seismic signals suggested that Strombolian explosions occurred at intervals of tens of seconds to minutes. The Washington VAAC reported that during clear weather on 3 July, a ~30-km-long ash plume was visible below ~3 km a.s.l.
Source: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program
| 19.514°N, 103.62°W
| Elevation 3850 m
On 29 June and 4 July low-level volcanic activity continued at Colima, with an average of three ash explosions occurring daily. The resultant ash plumes did not exceed heights of 2 km above the crater.
Source: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima
| 14.473°N, 90.88°W
| Elevation 3763 m
During 1-6 July, small explosions at Fuego produced plumes to ~1.4 km above the volcano that predominately drifted SW. Occasional avalanches of volcanic material traveled down ravines flanking the volcano.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
Seismicity at Karymsky was above background levels during 24-28 June, with 300-400 shallow earthquakes occurring. During 29-30 June, the number of earthquakes increased to 600-950. Based on interpretations of seismic data, daily ash-and-gas explosions may have risen to 2.5-4.5 a.s.l. On 28 June ash-and-gas plumes rose to 2.5-3 km every 7-10 minutes. Karymsky remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 29 June to 6 July, lava continued to flow down the Pulama pali scarp and small amounts flowed into the sea. In addition, vents at Pu`u `O`o cone were incandescent. A few small earthquakes continued beneath Kilauea's summit, but no tremor was recorded. Tremor at Pu`u `O`o was at moderate-to-high levels. A relatively large deflation event occurred on 29 June, with no obvious accompanying changes in eruptive activity.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 11.985°N, 86.165°W
| Elevation 594 m
On 4 July at 0615, a narrow plume of steam and/or ash from Masaya was visible on satellite imagery extending to the SW. By 0715 the plume extended ~12 km from the summit.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| 14.757°N, 91.552°W
| Elevation 3745 m
During 1-6 July weak-to-moderate explosions occurred at the Santa María lava-dome complex, producing plumes to a maximum height of ~1.5 km above the volcano. Several partial lava-dome collapses produced avalanches that traveled down the sides of Caliente cone.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
Seismicity was above background levels at Shiveluch during 25 June to 2 July, with several shallow earthquakes occurring beneath the active lava dome. Gas-and-steam plumes were seen rising to ~3.5 km a.s.l. Shiveluch remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
Volcanic and seismic activity at Soufrière Hills were at low levels during 25 June to 2 July. The seismic network recorded 2 long-period earthquakes, 6 volcano-tectonic earthquakes, 5 hybrid earthquakes, and 8 rockfalls. A peak sulfur-dioxide flux of ~365 metric tons was measured on 27 June.
Source: Montserrat Volcano Observatory (MVO)
| Ryukyu Islands (Japan)
| 29.638°N, 129.714°E
| Elevation 796 m
Based on information from JMA, the Tokyo VAAC reported that several explosions occurred at Suwanose-jima during 30 June to 5 July. The highest rising plume reached ~1.9 km a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
During 29 June to 5 July the level of volcanic and seismic activity diminished at Tungurahua in comparison to the previous week, with sporadic moderate explosions of ash and gas. The highest rising plume reached ~1.5 km above the volcano. During the report period, seismicity was at relatively low levels.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
| New Britain (Papua New Guinea)
| 5.05°S, 151.33°E
| Elevation 2334 m
During 2-6 July, thin plumes from Ulawun were visible on satellite imagery at heights around 3 km a.s.l. extending as far as ~90 km.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| United States
| 56.17°N, 159.38°W
| Elevation 2507 m
Short intervals of volcanic tremor occurred at Veniaminof during 25 June to 2 July. AVO reported that the tremor could be indicative of small, low-level ash-and-steam emissions. Small amounts of dark ash were seen in the ice-filled caldera on 27 June. Veniaminof remained at Concern Color Code Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
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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