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- Extrusion #7: Current
- Extrusion #6: July 2005 to ???
- Image with annotation and insets, October 30, 2005
-- Mount St. Helens' crater and dome with views of the "whalebacks" as they once looked, October 30, 2005, JPG format, 521 K
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Graphic, aerial image, August 10, 2005
-- Mount St. Helens, dome extrusions, from Press Briefing of September 2005, PDF Format, 2.2 M
- Extrusion #5: April 2005 to July 2005
- Extrusion #4: December 2004 to April 2005
- Extrusion #3: October to December 2004
- Extrusion #1 and #2: October 2004
(Sources: Daily Updates and Press Briefing of September 2005:)
July 5, 2007
Source: Information release from February 21, 2008:
Dome Dimensions:
Length (northwest-southeast): 3,725 feet
Width (northeast-southwest): 1,900 feet
High point on dome: 7,585 feet above sea level
Low point on crater rim (Shoestring Notch): 7,780 feet
Elevation difference between high point on dome and Shoestring Notch on the crater rim: 195 feet
Area: 487,000 square meters; 5.2 million square feet (0.19 square miles)
Volume: 122 million cubic yards (volume is equivalent to 150 to 200 large sports stadiums)
Extrusion rate on February 21, 2008: zero
Average extrusion rate between April 20, 2007 and July 5, 2007: 0.14 cubic yards/s (nearly equivalent to filling four Olympic-sized swimming pools every day)
Extrusion rate between October 21, 2006 and December 12, 2006: 0.88 cubic yards/s (nearly equivalent to filling 25 Olympic-sized swimming pools every day)
April 20, 2007
Source: Preliminary Digital Elevation Model (DEM) of April 20, 2007:
The volume of the new lava dome measured April 20, 2007, was 91.7 million cubic meters (larger than the 1980-1986 lava dome) and was growing at an average rate of 0.27 cubic meters per second.
December 6, 2006
Source: Preliminary Digital Elevation Model (DEM) of December 6, 2006:
The volume of the lava dome measured December 6, 2006, was 89.5 million cubic meters and was growing at an average rate of less than 1/2 cubic meter per second.
October 21, 2006
Source: Preliminary Digital Elevation Model (DEM) of October 21, 2006:
The volume of the lava dome measured October 21, 2006, was 87.7 million cubic meters and was growing at an average rate of less than 1/2 cubic meter per second.
The dome's high point was 2,350 meters (7,710 feet), with long-axis length being 1,030 meters (3,380 feet) and width being 525 meters (1,723 feet).
August 18, 2006
Source: Preliminary Digital Elevation Model (DEM) of August 18, 2006:
The volume of the lava dome measured August 18, 2006, was 85.0 million cubic meters and was growing at an average rate of less than 1/2 cubic meter per second. This volume is approximately equal to 150 Rose Garden Arenas (Portland, Oregon).
The dome's high point was 2,369 meters (7,772 feet), with long-axis length being 1,010 meters (3,314 feet) and width being 510 meters (1,678 feet).
April 18, 2006
Source: Preliminary Digital Elevation Model (DEM) of April 18, 2006:
The volume of the dome measured April 18, 2006, was 81.0 million cubic meters.
The high point was 2,336 meters (7,664 feet), with long-axis length (roughly NW/SE) being 945 meters (3,100 feet) and width (roughly SW/NE) being 500 meters (1,640 feet).
March 2006
Source: Daily Update, March 2, 2006:
The new dome’s summit altitude currently is about 7,550 feet, towering about 400 feet above the 1980s dome as seen from the U.S. Forest Service’s Coldwater visitor center. But that’s still below the 7,770-foot altitude reached last July, before collapse of a previous spine, and well below the crater rim, which is mostly above 8,100 feet except at Shoestring Notch or northward where the crater opens outward toward the roadheads.
February 9, 2006
Source: Preliminary Digital Elevation Model (DEM) of February 9, 2006:
The volume of the dome measured on February 9, 2006, was 77.4 million cubic meters.
January 2006
Source: Daily Update, January 26, 2006:
Initial analysis of recent photographs from fixed cameras in the crater show that the top of the currently active part of the new lava dome is at an altitude of about 2,240 meters (7,350 feet), which is about 90 meters (300 feet) higher than it was in early November 2005. On several occasions during the eruption, parts of the dome have been considerably higher, for instance 2,365 meters (7,765 feet) in July 2005. Those high points have since been lowered by disintegration, but still are higher than the top of the currently active part.
December 15, 2005
Source: Daily Update, February 14, 2006:
No significant changes in patterns of earthquakes or ground deformation have occurred over the past day. Analysis of a digital elevation model made from photographs taken on December 15, 2005, shows that the volume of the new lava dome at that time was about 73 million cubic meters (95 million cubic yards). Previously we had estimated that the new dome probably surpassed the volume of the 1980-1986 lava dome (77 million cubic meters or 100 million cubic yards) by the end of 2005. But it looks like that milestone might not have been met until recently. A model to be made from photographs taken on February 8, 2006, will tell us in a few weeks.
October 24, 2005
Source: Daily Update, December 13, 2005:
The volume of the dome measured on October 24, 2005, was 70 million cubic meters — about 90% of the volume of the 1980-to-1986 dome.
September 20, 2005
Source: Preliminary Digital Elevation Model (DEM) of September 20, 2005:
The volume of the dome measured on September 20, 2005, was 67.3 million cubic meters.
August 10, 2005
Source: Daily Update, October 18, 2005:
The latest digital elevation model of the new lava dome, which was created from aerial photographs taken on August 10, shows that the volume had grown to 62 million cubic meters (81 million cubic yards). The average rate of growth during late July and early August was about 2 cubic meters per second, a rate that has typified most of 2005.
July 14, 2005
Source: Daily Update, August 16, 2005:
Analysis of a digital elevation model from July shows that the volume of the new dome is about 58 million cubic meters (76 million cubic yards), almost 75 percent of the volume of the 1980s lava dome. The new dome continues to grow at a rate of about 1.3 cubic meters per second (almost 2 cubic yards per second).
June 23, 2005
Source: Daily Update, June 23, 2005:
Analyses of images from the USGS camera at the crater mouth reveal that the smooth lava spine continues to grow. The spine is presently about 160 m (525 ft) tall from ground level to its top, and it stands about 180 m (600 ft) higher than the old lava dome. It is now taller than it has ever been. In the coming days and weeks rockfalls are likely to occur.
June 15, 2005
Source: Daily Update, July 22, 2005:
Analysis of a digital elevation model created from aerial photographs taken on June 15 shows that the volume of the new lava dome is about 54 million cubic meters (70 million cubic yards), or about 60% of the volume of the lava dome that grew in the crater from 1980 to 1986. The rate of addition of lava to the dome from mid-May to mid-June remained at about 1.5 cubic meters (2 cubic yards) per second. The high point of the lava dome (the actively growing spine) on June 15 was 2,335 meters (7,660 feet), but it is currently lower than that owing to the recent large rockfalls from the spine.
April 19, 2005
Source: Daily update, May 27, 2005:
Analysis of a digital elevation model produced from aerial photographs taken on 19 April shows that the new lava dome had reached a volume of 47.5 million cubic meters (about 62 million cubic meters [sic, yards]). We have changed the method by which we compute the volume of the dome, so this figure isn’t directly comparable to results we’ve given in the past (by the older method the new volume is about 55 million cubic meters). The rate of addition of lava to the dome remains roughly constant at about 1.5 cubic meters (2 cubic yards) per second.
March 10, 2005
Source: Daily Update, May 3, 2005:
We discovered an error in the update of April 23 that gave the March 10 volume of the new lava dome and area of uplift as 62 million cubic yards. The correct volume on that date was 58 million cubic yards (45 million cubic meters)***. The highest point on the new dome was about 7675 feet, which was more than 500 feet above the top of the old lava dome. Since then, the dome has gone through a period of disintegration and spreading as it continues to increase in volume, so the high point is probably now somewhat lower.
*** (recalculation, volume dome extrusion only, 41.9 cubic meters)
March 10, 2005
Source: Daily Update, April 23, 2005:
Analysis of aerial photographs indicates that as of March 10 the topographic changes in the crater resulting from growth of the new dome and consequent glacier deformation have a combined volume of about 62 million cubic yard***. The current eruption has thus far caused a total topographic change in the crater that is equivalent to about two-thirds the volume of the old lava dome.
*** (corrected figure to 58 million cubic yards, see information of March 10, 2005, in Daily Update of May 3, 2005)
*** (recalculation, volume dome extrusion only, 41.9 cubic meters)
February 21, 2005
Source: Preliminary Digital Elevation Model (DEM) of February 21, 2005:
The volume of the dome measured on February 21, 2005, was 39.2 million cubic meters.
February 21, 2005
Source: Daily Update, March 23, 2005:
Results from analysis of imagery of 21 February show that the highest part of the new lava dome stands at an altitude of 7,682 feet, 527 higher than the old lava dome, and 92 feet below the level of Shoestring Notch on the southeast crater.
February 1, 2005
Source: Daily Update, February 20, 2005:
Further analysis of recent aerial photos reveals that as of February 1, the whaleback-shaped extrusion is about 1,550 feet long and 500 feet wide. The new dome and uplifted welt of crater floor and deformed glacier ice have grown to a combined volume of about 50 million cubic yards***, almost one-half the volume of the old lava dome.
*** (recalculation, volume dome extrusion only, 35.1 cubic meters)
February 1, 2005
Source: Daily Update, February 19, 2005:
Analysis of recent aerial photos reveals that as of February 1, the high point on the whaleback reached to an altitude of 7,650 feet, nearly 1,400 feet above the 1980 crater floor and 500 feet above the top of the old lava dome. The top of the new dome is now only about 130 feet below the level of Shoestring Notch on the southeast crater rim and about 700 feet below the south crater rim.
January 3, 2005
Source: Daily Update, January 26, 2005:
At yesterday’s press briefing there was a lot of interest in gaining better perspective about the size of the uplifted welt and new lava dome. The total volume change represented by the welt and dome as of 3 January of this year is 34 million cubic meters (or 44 million cubic yards)***. For Portlanders, that is equivalent to 134 Rose Garden arenas. The area of the dome and uplift covers about 60 city blocks. In Portland an equivalent area would extend from the Morrison Bridge to the Hawthorne Bridge and from the Willamette River to the Park Blocks. The top of the new lava dome rises about 550 feet above the pre-eruption surface of the flanking glacier. But the lava dome probably extends to the base of the glacier, which means that its true height is closer to 1100 feet.
*** (recalculation, volume dome extrusion only, 30.5 cubic meters)
December 11, 2004
Source: Preliminary Digital Elevation Model (DEM) of December 11, 2004:
The volume of the dome measured on December 11, 2004, was 25.5 million cubic meters.
November 29, 2004
Source: Preliminary Digital Elevation Model (DEM) of November 29, 2004:
The volume of the dome measured on November 29, 2004, was 25.5 million cubic meters.
November 2004, end of the month
Source: Daily Update, December 21, 2004:
As of the end of November, the “whaleback” measured about 500 m long, about 200 m wide, and its highest point, which extends above the old lava dome, reached about 275 m above the old crater floor. The volumetric change associated with emplacement of new lava (the new dome, uplift, and glacier deformation) was about 28 million cubic meters***. The old lava dome, which grew from 1980-86, has a volume of about 80 million cubic meters.
*** (recalculation, volume dome extrusion only, 21.3 cubic meters)
November 2004
Source: Daily Update, November 11, 2004:
Good viewing conditions revealed continued growth of the lava dome. Current estimates are that the welt, the broad area of deformation, is about 600 m (about 1950 feet) in diameter. The new lava dome, which occupies the central and western parts of the welt, is about 400 by 180 m (1300 by 600 feet). The highest point on the new lava dome is about 250 m (820 feet) above the former surface of the glacier that occupied that point in mid-September. Maximum surface temperatures on the new dome remain at about 700 degrees C (1300 degrees F). GPS instruments on the welt show rates of movement of up to several meters per day, while GPS instruments on the 1980-86 lava dome show movements of up to 1-2 cm (less than one inch) per day northward, away from the growing welt and new dome.
November 4, 2004
Source: Daily Update, November 10, 2004:
The latest estimate of the volume of the uplifted area and new lava dome from detailed analysis of aerial photographs taken on 4 November is about 20 million cubic meters (26 million cubic yards)***. This compares with volumes of about 5 million cubic meters on 4 October and 12 million cubic meters on 13 October. The apparent decrease in rate of volume change (7 million cubic meters in the earlier 9-day period versus 8 million cubic meters in the later 22-day period) doesn’t take into account millions of cubic meters of glacier ice that have been removed from a large part of the area of uplift. Work is underway to assess this effect. The 20-million-cubic-meter volume of the new uplift and lava dome is now more than 25% of the volume of the lava dome that grew in the crater between 1980 and 1986.
*** (recalculation, volume dome extrusion only, 11.8 cubic meters)
November 4, 2004
Source: Daily Update, November 9, 2004:
The latest estimate of the volume of the uplifted area and new lava dome from detailed analysis of aerial photographs taken on 4 November is about 20 million cubic meters (26 million cubic yards)***. This compares with volumes of about 5 million cubic meters on 4 October and 12 million cubic meters on 13 October. The apparent decrease in rate of volume change (7 million cubic meters in the earlier 9-day period versus 8 million cubic meters in the later 22-day period) doesn’t take into account millions of cubic meters of glacier ice that have been removed from a large part of the area of uplift. Work is underway to assess this effect. The 20-million-cubic-meter volume of the new uplift and lava dome is now more than 25% of the volume of the lava dome that grew in the crater between 1980 and 1986.
*** (recalculation, volume dome extrusion only, 11.8 cubic meters)
October 2004
Source: Daily Update, October 21, 2004:
Geological and thermal-imaging observations confirmed that both the area of uplift and the new lava extrusion have increased in size noticeably since last seen on October 14. The area of uplift and intense deformation continues to move southward and is nearing the crater wall. About 1 foot of new snow with a light dusting of ash covers much of the uplift, except for the new lava extrusion, which is steaming heavily. The new lava extrusion, which occupies the western part of the uplift, is now about 900 ft long by 250 ft wide and 230 ft high and has a volume of almost 2 million cubic yards. Its maximum temperature is about 600 degrees C (1100 degrees F). Rock samples from the new lava extrusion were collected from a helicopter by using a bucket slung on a 100-ft line. The samples look like typical Mount St. Helens lava, called dacite. Further detailed analyses of the samples will help to answer questions about the character of the magma driving the eruption and how it relates to lava erupted in the 1980s. A gas-sensing flight detected low levels of the volcanic gases carbon dioxide, sulfur dioxide, and hydrogen sulfide, which is consistent magma continuing to rise from depth.
October 13, 2004
Source: Preliminary Digital Elevation Model (DEM) of October 13, 2004:
The volume of the dome measured on October 13, 2004, was 542 thousand cubic meters.
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