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D. A. Swanson

Publications and source records attributed to D. A. Swanson.

34 records · Page 2Linked to original sources
USGS1982

Geologic map of the Wenatchee 1:100,000 Quadrangle, central Washington

The rocks and deposits within the Wenatchee quadrangle can be grouped into six generalized units: (1) Precambrian(?) Swakane Biotite Gneiss in the northeastern part of the quadrangle and the probable Jurassic low-grade metamorphic suite, mostly composed of the Easton Schist, in the southwestern part; (2) the Mesozoic Ingalls Tectonic Complex; (3) the Mesozoic Mount Stuart batholith; (4) lower and middle Tertiary nonmarine sedimentary and volcanic rocks; (5) Miocene basalt flows and interbedded epiclastic rocks constituting part of the Columbia River Basalt Group and interbedded silicic volcaniclastic rocks of the Ellensburg Formation; and (6) Pliocene to Holocene alluvium, glacial, flood, and mass-wastage deposits.

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USGS1976

Earthquakes and related catastrophic events, Island of Hawaii, November 29, 1975: A preliminary report

The largest earthquake in over a century--magnitude 7.2 on the Richter Scale--struck Hawaii the morning of November 29, 1975, at 0448. It was centered about 5 km beneath the Kalapana area on the southeastern coast of the island at 19° 20.1 ' N., long 155° 01.4 ' W.). The earthquake was preceded by numerous foreshocks, the largest of which was a 5.7-magnitude jolt at 0336 the same morning, and was accompanied, or closely followed, by a tsunami seismic sea wave), massive ground movements, hundreds of aftershocks, and a volcanic eruption. The tsunami reached a height of 12.2-14.6 m above sea level on the southeastern coast about 25 km west of the earthquake center, elsewhere generally 8 m or less. The south flank of Kilauea Volcano, which forms the southeastern part of the island, was deformed by dislocations along old and new faults along a 25-km long zone. Downward and seaward fault displacements resulted in widespread subsidence, locally as much as 3.5 m, leaving coconut palms standing in the sea and nearly submerging a small, near-shore island. A brief, small-volume volcanic eruption, triggered by the earthquake and associated ground movements occurred at Kilauea's summit about three-quarters of an hour later. The earthquake, together with the tsunami it generated, locally caused severe property damage in the southeastern part of the island; the tsunami also caused two deaths. Damage from the earthquake and related catastrophic events is estimated by the Hawaii Civil Defense Agency at about $4.1 million. The 1975 Kalapana earthquake and accompanying events represent the latest events in a recurring pattern of behavior for Kilauea. A large earthquake of about the same magnitude, tsunami, subsidence, and eruption occurred at Kilauea in 1868, and a less powerful earthquake and similar related processes are believed to have occurred in 1823. Indeed, the geologic evidence suggests that such events have been repeated many times in Kilauea's past and will continue. The 1975 events serve as a critical, though tragic, reminder of the dynamic nature of the volcano and point up the need for careful land-use planning and adequate building codes to minimize damage and loss of life from similar events in the future. Detailed scientific study of the cause and effects of the November 29, 1975, event will take many months. This report summarizes information available in February 1976.

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USGS1976

Tragedy at Kilauea

The following article is a reconstruction of events surrounding the deaths of a party of Hawaiian warriors in 1790 on Kilauea Volcano. It suggests that they were killed by a very hot, ash-free, base-surge cloud that rushed from the volcano. Much more recently than that, in the early morning hours of November 29, 1975, the largest earthquake in more than 100 years struck the southern part of the Island of Hawaii, causing widespread faulting and subsidence, an eruption at the summit of Kilauea Volcano, the loss of at least one life, and widespread damage to property. The effects of this earthquake are still being analyzed by the staff of the Geological Survey's Hawaiian Volcano Observatory, but preliminary results indicate that much of the south flank of Kilauea Volcano moved seaward in an abrupt, slump-like manner. The eruption that followed was small by the usually Kilauea standards and is regarded as a leakage of lava from the volcano's underground reservoir system in response to the effects of the earthquake. A more detailed account of these events will be included in a future issue of the Earthquake Information Bulletin.

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USGS1972

The complex filling of alae crater, Kilauea Volcano, Hawaii

Since February 1969 Alae Crater, a 165-m-deep pit crater on the east rift of Kilauea Volcano, has been completely filled with about 18 million m 3 of lava. The filling was episodic and complex. It involved 13 major periods of addition of lava to the crater, including spectacular lava falls as high as 100 m, and three major periods of draining of lava from the crater. Alae was nearly filled by August 3, 1969, largely drained during a violent ground-cracking event on August 4, 1969, and then filled to the low point on its rim on October 10, 1969. From August 1970 to May 1971, the crater acted as a reservoir for lava that entered through subsurface tubes leading from the vent fissure 150 m away. Another tube system drained the crater and carried lava as far as the sea, 11 km to the south. Much of the lava entered Alae by invading the lava lake beneath its crust and buoying the crust upward. This process, together with the overall complexity of the filling, results in a highly complicated lava lake that would doubtless be misinterpreted if found in the fossil record.

Hawaii↗
USGS1972

Magma supply rate at Kilauea volcano, 1952-1971

The three longest Kilauea eruptions since 1952 produced lava at an overall constant rate of about 9 x 10 6 cubic meters per month (vesicle-free). This is considered to represent the rate of magma supply from a deep source, probably the mantle, because little or no summit deformation indicating high-level storage accompanied any of the three eruptions.

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