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G. E. Ulrich

Publications and source records attributed to G. E. Ulrich.

At least 19 recordsLinked to original sources
USGS1992

Petrology of lavas from episodes 2-47 of the Puu Oo eruption of Kilauea Volcano, Hawaii: Evaluation of magmatic processes

The Puu Oo eruption of Kilauea Volcano in Hawaii is one of its largest and most compositionally varied historical eruptions. The mineral and whole-rock compositions of the Puu Oo lavas indicate that there were three compositionally distinct magmas involved in the eruption. Two of these magmas were differentiated (<6.8 wt% MgO) and were apparently stored in the rift zone prior to the eruption. A third, more mafic magma (9-10 wt% MgO) was probably intruded as a dike from Kilauea's summit reservoir just before the start of the eruption. Its intrusion forced the other two magmas to mix, forming a hybrid that erupted during the first three eruptive episodes from a fissure system of vents. A new hybrid was erupted during episode 3 from the vent where Puu Oo later formed. The composition of the lava erupted from this vent became progressively more mafic over the next 21 months, although significant compositional variation occurred within some eruptive episodes. The intra-episode compositional variation was probably due to crystal fractionation in the shallow (0.0-2.9 km), dike-shaped (i.e. high surface area/volume ratio) and open-topped Puu Oo magma reservoir. The long-term compositional variation was controlled largely by mixing the early hybrid with the later, more mafic magma. The percentage of mafic magma in the erupted lava increased progressively to 100% by episode 30 (about two years after the eruption started). Three separate magma reservoirs were involved in the Puu Oo eruption. The two deeper reservoirs (3-4 km) recharged the shallow (0.4-2.9 km) Puu Oo reservoir. Recharge of the shallow reservoir occurred rapidly during an eruption indicating that these reservoirs were well connected. The connection with the early hybrid magma body was cut off before episode 30. Subsequently, only mafic magma from the summit reservoir has recharged the Puu Oo reservoir. ?? 1992 Springer-Verlag.

Bulletin of Volcanology↗
USGS1990

Horizontal ground deformation patterns and magma storage during the Puu Oo eruption of Kilauea volcano, Hawaii: episodes 22-42

Horizontal ground deformation measurements were made repeatedly with an electronic distance meter near the Puu Oo eruption site approximately perpendicular to Kilauea's east rift zone (ERZ) before and after eruptive episodes 22-42. Line lengths gradually extended during repose periods and rapidly contracted about the same amount following eruptions. The repeated extension and contraction of the measured lines are best explained by the elastic response of the country rock to the addition and subsequent eruption of magma from a local reservoir. The deformation patterns are modeled to constrain the geometry and location of the local reservoir near Puu Oo. The observed deformation is consistent with deformation patterns that would be produced by the expansion of a shallow, steeply dipping dike just uprift of Puu Oo striking parallel to the trend of the ERZ. The modeled dike is centered about 800 m uprift of Puu Oo. Its top is at a depth of 0.4 km, its bottom at about 2.9 km, and the length is about 1.6 km; the dike strikes N65?? E and dips at about 87??SE. The model indicates that the dike expanded by 11 cm during repose periods, for an average volumetric expansion of nearly 500 000 m3. The volume of magma added to the dike during repose periods was variable but correlates positively with the volume of erupted lava of the subsequent eruption and represents about 8% of the new lava extruded. Dike geometry and expansion values are used to estimate the pressure increase near the eruption site due to the accumulation of magma during repose periods. On average, vent pressures increased by about 0.38 MPa during the repose periods, one-third of the pressure increase at the summit. The model indicates that the dikelike body below Puu Oo grew in volume from 3 million cubic meters (Mm3) to about 10-12 Mm3 during the series of eruptions. The width of this body was probably about 2.5-3.0 m. No net long-term deformation was detected along the measured deformation lines. ?? 1990 Springer-Verlag.

Bulletin of Volcanology↗
USGS1975

Apollo 12 voice transcript pertaining to the geology of the landing site

This document is an edited record of the conversations between the Apollo 12 astronauts and mission control pertaining to the geology of the landing site. It contains all discussions and observations documenting the lunar landscape, its geologic characteristics, the rocks and soils collected, and the lunar surface photographic record along with supplementary remarks essential to the continuity of events during the mission. This transcript is derived from audio tapes and the NASA Technical Air-to-Ground Voice Transcription and includes time of transcription, and photograph and sample numbers. The report also includes a glossary, landing site amp, and sample table.

Final Report↗
USGS1974

Apollo 11 voice transcript pertaining to the geology of the landing site

On July 20, 1969, America's Eagle touched down in southwestern Mare Tranquillitatis beginning man's firsthand exploration of the moon. This document is an edited record of the conversations between astronauts Neil Armstrong and Edwin "Buzz" Aldrin, Jr., at Tranquility Base, and Bruce McCandless at Mission Control in Houston during the approximately 22 hours spent on the lunar surface. It includes additional commentary during their return to Earth. It is a condensation hopefully of all the verbal data having geological significance. All discussions and observations documenting the lunar landscape, its geologic characteristics, the rocks and soils collected, and the photographic record are retained along with supplementary remarks essential to the continuity of events during the mission. We have deleted the words of mechanical housekeeping and engineering data, attempting not to lose the personal and philosophical aspects of this intensely human experience. The sources of this verbal transcript are the complete audio tapes recorded during the mission and the Technical Air-to-Ground Voice Transcription published by NASA. The voice record is listed chronologically given in days, hours, minutes, and seconds. These are the Ground Elapsed Times (GET) after launch from Kennedy Space Center which was 9:32 a.m. EDT on July 16, 1969. Figure 1 shows the vicinity of the landing site that was described, sampled, and photographed by the Apollo 11 crewmen.

Final Report↗
USGS1973

Preliminary geologic investigation of the Apollo 17 landing site

The Apollo 17 lunar module (LM) landed on the flat floor of a deep valley that embays the mountainous highlands at the eastern rim of the Serenitatis basin. Serenitatis, the site of a pronounced mascon, is one of the major multi-ringed basins on the near side of the Moon. The Taurus-Littrow valley, which is radial to the Serenitatis basis, is interpreted as a deep graben formed by structural adjustment of lunar crustal material to the Serenitatis impact.

Book chapter↗
USGS1972

Preliminary geologic investigation of the Apollo 15 landing site

The Apollo 15 lunar module (LM) landed at longitude 03&deg;39'20'' E, latitude 26&deg;26'00'' N on the mare surface of Palus Putredinis on the eastern edge of the Imbrium Basin. The site is between the Apennine Mountain front and Hadley Rille. The objectives of the mission, in order of decreasing priority, were description and sampling of three major geologic features&mdash;the Apennine Front, Hadley Rille, and the mare.

Book chapter↗
USGS1972

Preliminary geologic investigation of the Apollo 16 landing site

The Apollo 16 landing site in the lunar central highlands encompassed terra plains and adjacent mountainous areas of hilly and furrowed terra. These morphologic units, representing important terrane types in the lunar highlands, had been interpreted as volcanic on most premission geologic maps. However, it became apparent during the mission that there are indeed few or no volcanic rocks or landforms at the site but rather that the area is underlain by a wide variety of impact-generated breccias.

Book chapter↗