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Thun, R, Akerlof CW, Alley P, Koltick D, Loveless RL, Meyer DI, Zumberge M, Bintinger D, Lundy RA, Yovanovitch DD, Ditzler WR, Finley DA, Loeffler FJ, Shibata EI, Stanfield KC.  1976.  Description of Drift Chambers Used in a Fermilab Experiment. Nuclear Instruments & Methods. 138:437-444.   10.1016/0029-554x(76)90308-6   AbstractWebsite

We give a detailed description of the drift chamber system used in a charm search at Fermilab. All important aspects of design and performance are discussed.

Faller, JE, Rinker RL, Zumberge M.  1978.  Plans for the development of a portable absolute gravimeter: A tool for studying non-tidal variations in gravity. Boll. Geofis.Teor. Appl. 20:355-362. Abstract
Faller, JE, Rinker RL, Zumberge MA.  1979.  Plans for the Development of a Portable Absolute Gravimeter with a Few Parts in 109 Accuracy. Tectonophysics. 52:107-116.   10.1016/0040-1951(79)90212-9   AbstractWebsite

Successful development of a few parts in 109 portable g apparatus (which corresponds to a height sensitivity of about 1 cm) would have an impact on large areas of geodynamics as well as having possible application to earthquake prediction. Furthermore, the use of such an instrument in combination with classical leveling or extraterrestrially determined height data would yield information on internal mass motions. The plans for the development of such an instrument at JILA using the method of free fall will be given. The proposed interferometric method uses one element of an optical interferometer as the dropped object. Recent work has resulted in substantial progress towards the development of a new type of long-period (T > 60 sec) suspension for isolating the reference mirror (corner cube) in the interferometer. Improvements here over the isolation methods previously available, together with state-of-the-art timing and interferometric techniques, are expected to make it possible to achieve a few parts in 109 accuracy with a field-type instrument.

Faller, JE, Rinker RL, Zumberge M.  1979.  Progress on the development of a portable absolute gravimeter. Bulletin d'Information. 44 Abstract
Zumberge, MA, Rinker RL, Faller JE.  1982.  A Portable Apparatus for Absolute Measurements of the Earths Gravity. Metrologia. 18:145-152.   10.1088/0026-1394/18/3/006   AbstractWebsite

We have developed a new and portable apparatus for making absolute measurements of the acceleration due to the Earth's gravity. We use the method of free fall, and interferometrically determine the acceleration of a freely falling cube corner. In the design and development of this instrument, particular attention was paid to those aspects which would affect its performance in the field. The resulting instrument, we believe, provides a viable new tool for the study of tectonic motions. The system is very small; it can be transported in a small van and requires only two hours for assembly. A high rate of data acquisition is available; if necessary, a single measurement can be made every two seconds. Further, we have made a concerted effort to detect and (we hope) eliminate systematic errors. The results of extensive tests indicate that the achievable accuracy for g is about six parts in 109. This instrument therefore provides a sensitivity to vertical motions (e.g., of the Earth's crust) as small as 2 cm.

Zumberge, MA, Faller JE, Gschwind J.  1983.  Results from an Absolute Gravity Survey in the United-States. Journal of Geophysical Research. 88:7495-7502.   10.1029/JB088iB09p07495   AbstractWebsite

Using the recently completed JILA absolute gravity meter, we made an absolute gravity survey which covered 12 sites in the United States. Over a period of 8 weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland, and Massachusetts. The time spent in carrying out a measurement at a single location was typically 1 day. A measurement accuracy of around 1×10−7 m/s2 (10 μGal) is believed to have been obtained at each of the sites.

Zumberge, M, Faller JE, Rinker RL.  1984.  A new portable, absolute gravimeter. Precision Measurements and Fundamental Constants II. ( Taylor BN, Philips WD, Eds.).:405-409. Abstract
Zumberge, MA.  1985.  Frequency Stability of a Zeeman-Stabilized Laser. Applied Optics. 24:1902-1904.   10.1364/AO.24.001902   AbstractWebsite

The frequency of a commercial hard-sealed He-Ne laser has been stabilized to the center of the discharge gain profile using the mode splitting caused by an axial magnetic field. The absolute frequency has been measured repeatedly during intermittent operation over 20 months. Its drift over most of this period has been 2.6 ± 0.7 MHz/yr. The lock point has been found to depend slightly on the laser tube’s temperature.

Zumberge, MA, Sasagawa G, Kappus M.  1986.  Absolute Gravity Measurements in California. Journal of Geophysical Research-Solid Earth and Planets. 91:9135-9144.   10.1029/JB091iB09p09135   AbstractWebsite

We have constructed an absolute gravity meter that determines the local gravitational acceleration by timing a freely falling mass with a laser interferometer. The instrument has made measurements at 11 sites in California, four in Nevada, and one in France. The uncertainty in the results is typically 10μGal (1 Gal ≡ 1 cm/s2; 1 μGal = 10−6 Gal = 10−8 m/s2). Repeated measurements have been made at several of the sites; only one shows a substantial change in gravity.

Arnautov, G, Boulanger Y, Cannizzo L, Cerutti G, Faller J, Feng Y-Y, Groten E, Guo Y, Hollander W, Huang D-L, Kalish E, Marson I, Niebauer T, Sakuma A, Sasagawa G, Schleglov S, Stus Y, Tarasiuk W, Ahang G-Y, Zhou J-H, Zumberge M.  1987.  Results of the Second International Comparison of Absolute Gravimeters in Sevres 1985. Bull. D'Information. 59 Abstract
Chave, AD, Zumberge MA, Ander ME, Hildebrand JA, Spiess FN.  1987.  Polar Ice Test of the Scale Dependence of G. Nature. 326:250-251.   10.1038/326250b0   AbstractWebsite
Johnson, HO, Wyatt F, Zumberge MA.  1988.  Stabilized Laser for Long Base-Line Interferometry. Applied Optics. 27:445-446.   10.1364/AO.27.000445   AbstractWebsite
Zumberge, MA, Wyatt FK, Yu DX, Hanada H.  1988.  Optical Fibers for Measurement of Earth Strain. Applied Optics. 27:4131-4138.   10.1364/AO.27.004131   AbstractWebsite

We report on laboratory experiments on single-mode optical fibers for use in measuring earth strain. We have monitored the long-term stability of 25-m long tensioned fibers and found their rates of fractional change in optical path lengths to be no more than 2 × 10-6/yr. The optical temperature coefficients for several fibers whose physical lengths were held constant were found to be within 4% of 1.17 × 10-5 apparent strain/°C. The strain sensitivity (the ratio of observed optical path change to physical path change) was determined to be within 1% of 1.16 for all the fibers tested. Initial field tests indicate that fibers are suitable for earth strain measurements of moderate precision.

Zumberge, MA.  1989.  Absolute gravity measurements. The Encyclopedia of solid earth geophysics. ( James DE, Ed.).:5-9., New York: Van Nostrand Reinhold Abstract
Ander, ME, Zumberge MA, Lautzenhiser T, Parker RL, Aiken CLV, Gorman MR, Nieto MM, Ferguson JF, McMechan GA.  1989.  A New Field Experiment in the Greenland Ice Cap to Test Newton Inverse Square Law. Annals of the New York Academy of Sciences. 571:672-680.   10.1111/j.1749-6632.1989.tb50553.x   AbstractWebsite

Recent experimental evidence suggests that Newton’s law of gravity may not be precise. There are modern theories of quantum gravity that, in their attempts to unify gravity with other forces of nature, predict non-Newtonian gravitational forces that could have ranges on the order of 102-105 m. If they exist, these forces would be apparent as violations of Newton’s inverse square law. A geophysical experiment was carried out to search for possible finite-range, non-Newtonian gravity over depths of 213-1673 m in the glacial ice of the Greenland ice cap. The principal reason for this choice of experimental site is that a hole drilled through the ice cap already existed and the uniformity of the ice eliminates one of the major sources of uncertainty arising in the first of earlier namely, the heterogeneity of the rocks through which a mine shaft or drill hole passes. Our observations were made in the summer of 1987 at Dye 3, Greenland, in the 2033-m-deep borehole, which reached the basement rock.

Ander, ME, Zumberge MA, Lautzenhiser T, Parker RL, Aiken CLV, Gorman MR, Nieto MM, Cooper APR, Ferguson JF, Fisher E, McMechan GA, Sasagawa G, Stevenson JM, Backus G, Chave AD, Greer J, Hammer P, Hansen BL, Hildebrand JA, Kelty JR, Sidles C, Wirtz J.  1989.  Test of Newtons Inverse-Square Law in the Greenland Ice Cap. Physical Review Letters. 62:985-988.   10.1103/PhysRevLett.62.985   AbstractWebsite

An Airy-type geophysical experiment was conducted in a 2-km-deep hole in the Greenland ice cap at depths between 213 and 1673 m to test for possible violations of Newton’s inverse-square law. An anomalous gravity gradient was observed. We cannot unambiguously attribute it to a breakdown of Newtonian gravity because we have shown that it might be due to unexpected geological features in the rock below the ice.

Sasagawa, GS, Zumberge MA, Stevenson JM, Lautzenhiser T, Wirtz J, Ander ME.  1989.  The 1987 Southeastern Alaska Gravity Calibration Range - Absolute and Relative Gravity Measurements. Journal of Geophysical Research-Solid Earth and Planets. 94:7661-7666.   10.1029/JB094iB06p07661   AbstractWebsite

In June 1987 a gravimeter calibration range was set up in southeastern Alaska and the Yukon territory, as part of a geophysical determination of the Newtonian gravitational constant. Absolute gravity measurements were made between the range endpoints using the Institute of Geophysics and Planetary Physics absolute gravity meter. The calibration range spans 171.841±0.014 mGal, with a midpoint g value of 9.81746500 ms−2. Relative gravity meters, including a LaCoste and Romberg borehole gravity meter, were read along this range. A scale factor correction (SFC) for borehole meter 14 was found to be (8.1 ± 1.5) × 10−4, and for meter G-349 the correction was (−3.3 ± 1.7) × 10−4. The SFC for meter D-85 has an upper bound of ±1.0 × 10−4.

Sasagawa, GS, Zumberge MA.  1989.  5-Year Frequency Stability of a Zeeman Stabilized Laser. Applied Optics. 28:824-825.   10.1364/AO.28.000824   AbstractWebsite

A five-year record of the lockpoint frequency of a Zeeman stabilized laser shows an observed drift rate of 0.3 ± 0.5 MHz/yr following an initial drift of 5.7 ± 2.2 MHz/yr in the first eighteen months of intermittent operation. A second Zeeman laser drifted at a rate of -0.8 ± 1.0 MHz/yr over the last 2.5 yr; the frequency drift was -0.2 ± 0.6 MHz/yr over the last 3.3yr. Empirical temperature correctionsto laser frequency measurements produce a slight variance reduction in the data but no effective bias in the drift estimates.

Fisher, E, McMechan GA, Gorman MR, Cooper APR, Aiken CLV, Ander ME, Zumberge MA.  1989.  Determination of Bedrock Topography beneath the Greenland Ice-Sheet by 3-Dimensional Imaging of Radar Sounding Data. Journal of Geophysical Research-Solid Earth and Planets. 94:2874-2882.   10.1029/JB094iB03p02874   AbstractWebsite

In the summer of 1987, approximately 42,600 radar reflections were obtained along 124 radial lines, 5 km long, centered at Dye 3 in southern Greenland. Processing of these data using a three-dimensional kinematic migration algorithm produces a high-resolution image of the rock surface topography beneath the ice sheet. Estimated uncertainties in the position of the rock surface increase where sampling is less dense, such as toward the edges of the survey, but are less than 5 m over most of the survey area. The main structure revealed is a northwest-southeast trending valley in the bedrock that crosses the westward regional dip of the rock surface. Ice thickness increases from approximately 1800 m in the east to approximately 2100 m in the west.

Parker, RL, Zumberge MA.  1989.  An Analysis of Geophysical Experiments to Test Newton Law of Gravity. Nature. 342:29-32.   10.1038/342029a0   AbstractWebsite

Signals reported as evidence for a non-newtonian 'fifth' force at a North Carolina television tower and elsewhere can be explained in a conventional way by postulating small density variations underground. The assumptions employed in earlier analyses which pointed to a failure of the inverse square law are examined and found to be difficult to justify.

Munk, W, Revelle R, Worcester P, Zumberge M.  1990.  Strategy for future measurements of very-low frequency sea-level change. National Research Council Report, Geophysics Study Committee. :221-227., Washington, D. C.: National Research Council Abstract
Hildebrand, JA, Stevenson JM, Hammer PTC, Zumberge MA, Parker RL, Fox CG, Meis PJ.  1990.  A Sea-Floor and Sea-Surface Gravity Survey of Axial Volcano. Journal of Geophysical Research-Solid Earth and Planets. 95:12751-12763.   10.1029/JB095iB08p12751   AbstractWebsite

Seafloor and sea surface gravity measurements are used to model the internal density structure of Axial Volcano. Seafloor measurements made at 53 sites within and adjacent to the Axial Volcano summit caldera provide constraints on the fine-scale density structure. Shipboard gravity measurements made along 540 km of track line above Axial Volcano and adjacent portions of the Juan de Fuca ridge provide constraints on the density over a broader region and on the isostatic compensation. The seafloor gravity anomalies give an average density of 2.7 g cm−3 for the uppermost portion of Axial Volcano, The sea surface gravity anomalies yield a local compensation parameter of 23%, significantly less than expected for a volcanic edifice built on zero age lithosphere. Three-dimensional ideal body models of the seafloor gravity measurements suggest that low-density material, with a density contrast of at least 0.15 g cm−3, may be located underneath the summit caldera. The data are consistent with low-density material at shallow depths near the southern portion of the caldera, dipping downward to the north. The correlation of shallow low-density material and surface expressions of recent volcanic activity (fresh lavas and high-temperature hydrothermal venting) suggests a zone of highly porous crust. Seminorm minimization modeling of the surface gravity measurements also suggest a low-density region under the central portion of Axial Volcano. The presence of low-density material beneath Axial caldera suggests a partially molten magma chamber at depth.

Ander, ME, Kerr W, Aiken CLV, Glover CC, Zumberge MA.  1990.  An Absolute Wireline Calibration to Support a Test of Newtons Inverse Square Law. Geophysics. 55:920-923.   10.1190/1.1442907   AbstractWebsite

As part of a Greenland ice cap experiment to measure possible scale length violations of Newton’s inverse square law over geophysical scales of 200 to 1500 m, it was necessary to locate the depth of a gravity meter attached to a wireline down a borehole to about 1 part in 10 000. In order to do this, the wireline and cable length measuring system had to be calibrated both before and after the Greenland expedition. The measuring system used a combination of a mechanical wheel measuring device and a magnetic mark counter. The calibration was conducted in a 1200 m vertical mine shaft at the Consolidated Silver Mine in Osborn, Idaho. Distances in the mine shaft were first calibrated to a precision of about 0.005 m using a geodetic laser system model 4L Geodimeter operating at 30 MHz. To calibrate the wireline, it was run up the mine shaft five times before and five times after the Greenland experiment. The calibration before the experiment was good to about 4 parts in 10 000 and the calibration after was accurate to about 1 part in 10 000. A total inelastic stretch of only 0.102 m occurred during the Greenland operation.

Zumberge, MA, Ander ME, Lautzenhiser TV, Parker RL, Aiken CLV, Gorman MR, Nieto MM, Cooper APR, Ferguson JF, Fisher E, Greer J, Hammer P, Hansen BL, McMechan GA, Sasagawa GS, Sidles C, Stevenson JM, Wirtz J.  1990.  The Greenland Gravitational Constant Experiment. Journal of Geophysical Research-Solid Earth and Planets. 95:15483-15501.   10.1029/JB095iB10p15483   AbstractWebsite

An Airy-type geophysical experiment was conducted in a 2-km-deep hole in the Greenland ice cap at depths between 213 m and 1673 m to test for possible violations of Newton's inverse square law. The experiment was done at Dye 3, the location of a Distant Early Warning Line radar dome and the site of the deepest of the Greenland Ice-Sheet Program (GISP) drill holes. Gravity measurements were made at eight depths in 183-m intervals with a LaCoste&Romberg borehole gravity meter. Prior to the experiment the borehole gravity meter was calibrated with an absolute gravity meter, and the wireline depth-rinding system used in the borehole logging was calibrated in a vertical mine-shaft against a laser geodimeter. The density of the ice in the region was calculated from measurements taken from ice cores obtained from earlier drilling observations. Ice penetrating radar was employed in order to correct the gravity data for the topography of the ice-rock interface. Surface gravity observations were made to assess the extent to which density variations in the sub-ice rock could affect the vertical gravity gradient. The locations of the gravity observation points were determined with a combination of GPS recording, first-order leveling, and EDM surveying. An anomalous variation in gravity totaling 3.87 mGal (3.87×10−5 m/s2) in a depth interval of 1460 m was observed. This may be attributed either to a breakdown of Newtonian gravity or to unexpected density variations in the rock below the ice.

Sasagawa, G, Zumberge MA.  1991.  Absolute Gravity Measurements in California, 1984-1989. Journal of Geophysical Research-Solid Earth and Planets. 96:2501-2513.   10.1029/90jb02283   AbstractWebsite

Repeated absolute gravity measurements have been made at 12 sites in California between 1984.3 and 1989.7. As determined in laboratory tests, the instrument used has an estimated accuracy of 10-mu-Gal (approximately 10(-8) g). The repeatability of the measurements is consistent with this accuracy assessment. No gravity changes above the limits set by instrumental uncertainty and environmental noise are observed in California during this period; the field observations provide upper limits on the rates of secular gravity changes which could be attributed to crustal deformation with a resolution corresponding to vertical displacement rates of 1-2 cm/yr.