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T.L. Holzer

Publications and source records attributed to T.L. Holzer.

30 records · Page 2Linked to original sources
USGS1993

Sand boils without earthquakes

Sedimentary deformation caused by liquefaction has become a popular means for inferring prehistoric strong earthquakes. In this report, we describe a new mechanism for generating such features in the absence of earthquakes. Sand boils and a 180-m-long sand dike formed in Fremont Valley, California, when sediment-laden surface runoff was intercepted along the upslope part of a 500-m-long preexisting ground crack, flowed subhorizonally in the crack, and then flowed upward in the downslope part of the crack where it discharged as sand boils on the land surface. If the sand boils and their feeder dike were stratigraphically preserved, they could be misinterpreted as evidence for earthquake-induced liquefaction.

Geology↗
USGS1989

State and local response to damaging land subsidence in United States urban areas

Land subsidence caused by man-induced depressuring of underground reservoirs has occurred in at least nine urban areas in the United States. Significant efforts to control it have been made in three areas: Long Beach, California; Houston-Galveston, Texas; and Santa Clara Valley, California. In these areas coastal flooding and its control cost more than $300 million. Institutional changes were required in each area to ameliorate its subsidence problem. In Long Beach and Houston Galveston, efforts were made to mitigate subsidence only after significant flood damage had occurred. To arrest subsidence at Long Beach, the city lobbied for a special state law, the California Subsidence Act, that required unitization and repressuring of the Wilmington oil field. In the Houston-Galveston region, the Texas State Legislature authorized formation of the Harris-Galveston Coastal Subsidence District with authority to regulate groundwater pumping by permit. This solution, which was achieved through efforts of entities affected by subsidence, was the product of a series of compromises necessitated by political fragmentation and disjointed water planning in the region. Amelioration of subsidence in the Santa Clara Valley was a collateral benefit from the effort by water users to curtail ground-water overdraft in the valley. Importation of surface water and a tax on ground-water pumpage reduced ground-water use, thereby allowing the recovery of water level and the arresting of subsidence.

Arizona, California, Georgia, Louisiana, Nevada, T↗
USGS1989

Dynamics of liquefaction during the 1987 Superstition Hills, California, earthquake

Simultaneous measurements of seismically induced pore-water pressure changes and surface and subsurface accelerations at a site undergoing liquefaction caused by the Superstition Hills, California, earthquake (24 November 1987; M = 6.6) reveal that total pore pressures approached lithostatic conditions, but, unexpectedly, after most of the strong motion ceased. Excess pore pressures were generated once horizontal acceleration exceeded a threshold value.

California↗
USGS1988

Parkfield, California, liquefaction prediction (USA)

The primary purpose of this short note is to formally record the liquefaction prediction (Holzer et al., 1986) made in connection with this predicted earthquake. In addition, this note serves to alert the seismic engineering community to special instrumentation being installed at the prediction site. The instrumentation will consist of 4 downhole accelerometers at depths ranging from 3-30 m, a surface accelerometer, 7 dynamic piezometers distributed in the sand strata between depths of 5 and 15 m, and a network of bench marks for measuring permanent ground deformation.

Califonia↗
USGS1986

Land subsidence

In November 1966, sixty percent of Venice, Italy, is inundated by a storm surge that causes waters in the Venetian lagoon to rise more than 6 feet. On December 28, 1971, a janitor at the Washington Elementary School in Johnston City, Illinois, discovers sever cracking of the school. In January 1972, the school is abandoned and subsequently razed. In the 1970's, five homes in New Orleans, Louisiana, are destroyed by gas explosins. In May 198, a 350 feet diameter sink-hole forms in a business area in Winter Park, Florida, and swallows a home and parts of several businesses. In August 1983, Hurricane Alicia slams into the texas Gulf Coast near Houston, Texas, and devastates the 500 home Brownwood subdivision on the north end of Galveston Bay. Homes are torn from their foundations and reduced to rubble.

Earthquakes & Volcanoes (USGS)↗
USGS1985

Land subsidence caused by ground water withdrawal in urban areas

At least eight urban areas in the world have encountered significant economic impact from land subsidence caused by pumping of ground water from unconsolidated sediment. The areas, most of which are coastal, include Bangkok, Houston, Mexico City, Osaka, San Jose, Shanghai, Tokyo, and Venice. Flooding related to decreased ground elevation is the principal adverse effect of the subsidence. Lesser effects include regional tilting, well-casing failures, "rising" buildings, and ground failure or rupture. Subsidence of most of these urban areas began before the phenomenon was discovered and understood. Thus, the subsidence problems were unanticipated. Methods to arrest subsidence typically have included control of ground water pumping and development of surface water to offset the reductions of ground water pumping. Ground water recharge has also been practiced. Areas threatened by flooding have been protected by extensive networks of dikes and sea walls, locks, and pumping stations to remove storm runoff. ?? 1985 D. Reidel Publishing Company.

GeoJournal↗
USGS1982

Differential compaction mechanism for earth fissures near Casa Grande, Arizona

Precise gravity measurements indicate that earth fissures or tension cracks caused by ground-water withdrawal within a 10-km 2 area southeast of Casa Grande, Arizona, are associated with relief on the buried interface between the alluvial aquifer and underlying bedrock. All of the fissure zones; which have a cumulative length of >8.7 km, occur above either ridges or steps in the bedrock surface. Intersecting fissure zones overlie intersecting bedrock features, and the angle of intersection of the zones accurately reflects the angle between the bedrock features. These relations suggest that the fissures are forming in response to localized differential compaction caused by localized variations of aquifer-system thickness. Topographic profiles across fissures on undisturbed desert floor confirm differential compaction proportional to the variations in aquifer thickness. The occurrence of the fissures at points of maximum convex-upward curvature in profiles of both the topographic and buried bedrock surfaces indicates that the fissures result from tensile strains caused by bending of the strata above the buried bedrock features in response to the differential compaction. Tensile strains at failure are estimated to range from ∼ 0.02% to 0.2% on the basis of modeling of the bending process.

Geological Society of America Bulletin↗
USGS1979

Elastic expansion of the lithosphere caused by groundwater withdrawal in south-central Arizona

Relative crustal uplift observed from 1948–1949 to 1967 in the Lower Santa Cruz River Basin in south-central Arizona is attributed at least in part to elastic expansion of the lithosphere induced by the removal, and subsequent loss by evapo transpiration, of 4.35 × 10 13 kg of groundwater from alluvium. The area of unloading is approximately 8070 km 2 . Uplift, relative to an apparently stable area west of the unloaded area, was observed in two areas near Casa Grande and Florence where crystalline bedrock is either close to the land surface or crops out through alluvium from which groundwater was withdrawn. The magnitudes of uplift were approximately 6.3 and 7.5 cm respectively. The observations are based on first-order leveling. The observations are significant at three standard deviations for random surveying errors, and are not believed to be affected by systematic errors. However, the 7.5-cm uplift observed at Florence may be from 1 to 2 cm in excess of the actual uplift because of the possibility of subsidence of a tie point due to groundwater pumping during the leveling in 1948–1949. Uplift is attributed to groundwater withdrawal on three bases. First, the observed uplift is consistent with a theoretical evaluation of elastic expansion based on linear elasticity theory. For the observed distribution of unloading and uplift and a Poisson's ratio of 0.25, a Young's modulus for the lithosphere of approximately 0.68 Mbar is implied. This value is comparable to values of the lithosphere reported elsewhere. Second, the magnitude of uplift compares favorably with the magnitude of elastic depression caused by the formation of Lake Mead, Arizona—Nevada, 430 km northwest of the study area, when allowance is made for the different magnitudes and areal distributions of surface (un)loading. And third, in the area near Casa Grande, a reversal in the sense of bedrock displacement form subsidence of tectonic origin to uplift approximately coincided with the beginning of large groundwater overdraft. The uplift from 1948 to 1967 near Casa Grande was preceded from 1905 to 1948 by 7–8 cm of tectonic subsidence; no precise data for the area near Florence are available before 1948.

Arizona↗