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NASA NTRSDate not supplied

Lunar TLP's and the Tectonic Processes of the Earth and the Moon

We study the transient lunar phenomena (TLP) as an indicator of lunar tectonic. Seismic phenomena can be used as a direct indicator of some tectonic activities of the planets The Moon-Earth gravitational interaction has been studied extensively as a triggering mechanism to geodynamics. In this work, we study the reverse interaction Earth-Moon in relation to the TLP activities. The lunar outgassing potentially is the leading cause for TLP activities resulting from the lunar interior's dynamic mechanism. We have studied Earth venting and earthquakes processes and have found that radon was frequently activated before significant seismic events due to Moon-Sun interaction with Earth (Ouzounov et al., 2018). Earthquake lights, an associated phenomenon reported before some major earthquakes, are analog to TLP activities on the moon. In 1972, N. Kozyrev suggested a possible moon response to the significant seismic events on Earth. To understand whether TLP's activities have any possible connection with Earth geodynamics, we perform a statistical check between the significant seismic activities from the NEIC catalog and lunar TLPs for 1907-1977 for four lunar areas :Aristarchus, Plato, Gassendi, and Alphonsus. We use TLP compiled catalog based on Middlehurst et al. (1968), Cameron (2006a,b), and Crotts (2008) catalogs. Our results revealed a causal relationship between significant earthquakes and TLP events. However, this relation varies from the location and depth of the seismic events. Deformation triggers the degassing process, and TLPs are indicators for those underlying activities. Our work can provide new information about the origin of TLP and the existence of a possible relationship between the tectonic processes of Earth and the Moon.

D Ouzonov↗
NASA NTRS1976

Numerical determination of the transmissibility characteristics of a squeeze film damped forced vibration system

Numerical solutions of the governing equations of motion of a liquid squeeze film damped forced vibration system were carried out to examine the feasibility of using a liquid squeeze film to cushion and protect large structures, such as buildings, located in areas of high seismic activity. The mathematical model used was that for a single degree of freedom squeeze film damped spring mass system. The input disturbance was simulated by curve fitting actual seismic data with an eleventh order Lagranging polynomial technique. Only the normal component of the seismic input was considered. The nonlinear, nonhomogeneous governing differential equation of motion was solved numerically to determine the transmissibility over a wide range of physical parameters using a fourth-order Runge-Kutta technique. It is determined that a liquid squeeze film used as a damping agent in a spring-mass system can significantly reduce the response amplitude for a seismic input disturbance.

Sutton, M. A.↗
NASA NTRS1980

Stress accumulated mechanisms on strike-slip faults

The tectonic framework causing seismicity on the San Andreas and North Anatolian faults can be understood in terms of plate tectonics. However, the mechanisms responsible for the distribution of seismicity in space and time on these faults are poorly understood. The upper part of the crust apparently behaves elastically in storing energy that is released during an earthquake. The relatively small distances from the fault in which stress is stored argue in favor of a plate with a thickness of 5-10 km. The interaction of this plate with a lower crust that is behaving as a fluid damps the seismic cycling in distances of the order of 10 km from the fault. Low measured heat flow also argues in favor of a thin plate with a low stress level on the fault. Future measurements of stress, strain, and heat flow should help to provide a better understanding of the basic mechanisms governing the behavior of strike-slip faults.

Turcotte, D. L.↗
NASA NTRS1985

Design, Fabrication and Testing of an Experimental Apparatus for Determining Particle Behavior Under Very Low Intergranular Stresses

Because the constitutive laws for soils are governed mainly by interparticle friction, all aspects of their mechanical behavior depend strongly on gravitational body forces. This fact poses serious limitations on the formulation of a materially objective soil constitutive theory, based on experimentation performed on Earth. In particular, the presence of the Earth's gravity prohibits the design of controlled experiments to properly simulate a variety of critical phenomena associated with the dynamic response of soils to seismic excitation in a very low effective confining stress field. For these reasons, laboratory-controlled experiments in the Space Shuttle, under essentially zero-gravity conditions, could offer invaluable opportunities for developing a quantitative understanding of fundamental aspects of soil behavior during or after an earthquake, which, in turn, could result in significant technological advances in geotechnical earthquake engineering.

Sture, S.↗
NASA NTRS1997

GPS Monitoring of Subduction Zone Deformation in Costa Rica

The subduction of the Cocos plate beneath Costa Rica is among the highest convergence rates in the world. The high subduction rate and nearness of the Nicoya Peninsula, Costa Rica to the Middle America Trench (MAT) provide a unique opportunity to map variations in interseismic strain of the crust above the seismogenic zone in response to variations in seismic coupling.

Cocos plate Costa Rica subduction rate seismic cou↗
NASA NTRS1985

Mechanical Stress Regulation of Plant Growth and Development

Growth dynamics analysis was used to determine to what extent the seismic stress induced reduction in photosynthetic productivity in shaken soybeans was due to less photosynthetic surface, and to what extent to lower efficiency of assimulation. Seismic stress reduces shoot transpiration rate 17% and 15% during the first and second 45 minute periods following a given treatment. Shaken plants also had a 36% greater leaf water potential 30 minutes after treatment. Continuous measurement of whole plant photosynthetic rate shows that a decline in CO2 fixation began within seconds after the onset of shaking treatment and continued to decline to 16% less than that of controls 20 minutes after shaking, after which gradual recovery of photosynthesis begins. Photosynthetic assimilation recovered completely before the next treatment 5 hours later. The transitory decrease in photosynthetic rate was due entirely to a two fold increase in stomatal resistance to CO2 by the abaxial leaf surface. Mesophyll resistance was not significantly affected by periodic seismic treatment. Temporary stomatal aperture reduction and decreased CO2 fixation are responsible for the lower dry weight of seismic stressed plants growing in a controlled environment.

Mitchell, C. A.↗
NASA NTRS1973

The effect of yield strength and ductility to fatigue damage

The cumulative damage of aluminium alloys with different yield strength and various ductility due to seismic loads was studied. The responses of an idealized beam with a centered mass at one end and fixed at the other end to El Centro's and Taft's earthquakes are computed by assuming that the alloys are perfectly elastoplastic materials and by using numerical technique. Consequently, the corresponding residual plastic strain can be obtained from the stress-strain relationship. The revised Palmgren-Miner cumulative damage theorem is utilized to calculate the fatigue damage. The numerical results show that in certain cases, the high ductility materials are more resistant to seismic loads than the high yield strength materials. The results also show that if a structure collapse during the earthquake, the collapse always occurs in the very early stage.

Yeh, H. Y.↗
NASA NTRS1994

Analysis of coseismic surface displacement gradients using radar interferometry: New insights into the Landers earthquake

The map of the coseismic displacement field generated by interferometric processing of synthetic aperture radar (SAR) images taken before and after the June 28, 1992, Landers earthquake sequence brings new insights into the nature of deformation caused by these earthquakes. We use the interferometric map generated by Massonnet et al. (1993) to analyze the surface displacement field in the vicinity of the fault trace. Complexities in the fringe pattern near the fault reflect short-wavelength variations of the surface rupture and slip distribution, and attest to large displacement gradients. Along two sections of the fault, characteristic fringe patterns can be recognized, contrasting in density and direction with patterns observed away from the rupture. In order to understand the observed fringe patterns, we compute synthetic interferograms in three simple cases: (1) rigid-body rotations about a vertical axis, (2) about a horizontal axis (tilt), and (3) distributed, simple shear. The orientation and spatial separation of interferometric fringes predicted by these models help constrain near-field deformation and rupture parameters. Where the Kickapoo fault connects with the Homestead Valley fault, the interferogram shows a clear pattern of parallel N20 deg W fringes separated by about 160 m. This pattern and vertical offsets measured along the Kickapoo fault suggest that the block between this fault and the Johnson Valley fault may have been tilted, down to the west. A 5-km block lifted by 1 m on one side would be tilted by an angle of 0.01 deg (190 microrad), producing fringes separated by about 160 m, parallel to the tilt axis. Such a tilt, parallel to a N20 deg W direction, would account for the gradual, northward increase of the vertical slip component observed along the Kickapoo fault. This tilt may also explain the 1 m of reverse slip observed along the 'slip gap' section of the Homestead Valley break. Between the southern end of the Johnson Valley fault and the Eureka Peak fault, where no surface rupture has been mapped, the dense pattern of fringes implies distributed shear, probably resulting from fault slip at depth. The density and direction of the fringes in the gap are consistent with a right-lateral slip of 1.2-3.8 m on a blind fault locked above the depth of 1.5-2 km. Such observations of small wavelength features in the SAR interferogram bring new insights into the near-field displacement gradient and thus on response of the uppermost crust to seismic rupture.

Peltzer, Gilles↗
NASA NTRS2004

Near Space Tracking of the EM Phenomena Associated with the Main Earthquakes

Searching for electromagnetic (EM) phenomena originating in the Earth's crust prior to major earthquakes (M>5) are the object of this exploratory study. We present the idea of a possible relationship between: (1) electro-chemical and thermodynamic processes in the Earth's crust and (2) ionic enhancement of the atmosphere/ionosphere with tectonic stress and earthquake activity. The major source of these signals are proposed to originate from electromagnetic phenomenon which are responsible for these observed pre-seismic processes, such as, enhanced IR emission, also born as thermal anomalies, generation of long wave radiation, light emission caused by ground-to-air electric discharges, Total Electron Content (TEC) ionospheric anomalies and ionospheric plasma variations. The source of these data will include: (i) ionospheric plasma perturbations data from the recently launched DEMETER mission and currently available TEC/GPS network data; (ii) geomagnetic data from ORSTED and CHAMP; (iii) Thermal infra-red (TIR) transients mapped by the polar orbiting (NOAA/AVHRR, MODIS) and (iv) geosynchronous weather satellites measurements of GOES, METEOSAT. This approach requires continues observations and data collecting, in addition to both ground and space based monitoring over selected regions in order to investigate the various techniques for recording possible anomalies. During the space campaign emphasis will be on IR emission, obtained from TIR (thermal infrared) satellites, that records land/sea surface temperature anomalies and changes in the plasma and total electron content (TEC) of the ionosphere that occur over areas of potential earthquake activity.

Ouzounov, Dimitar↗
NASA NTRS2023

Seismic Assessment of a Long-Term Lunar Habitat

The establishment of secure earth-independent long-term lunar habitats has been envisioned by numerous government agencies and private companies. Recent advancements in assessing seismic hazards caused by shallow moonquakes have highlighted the importance of incorporating this phenomenon into the design of robust and resilient lunar structures. However, further research is required to explore lunar habitat design that considers seismic loads. This paper proposes assessing the structural response of a lunar habitat made of sulfur concrete covered with a regolith layer. The numerical model of the structure is subjected to gravitational, internal pressure and seismic loads. The seismic analysis of the structure is carried out using spectral and nonlinear time history methods. Conditional mean spectra for shallow moonquakes with return periods of 75, 475, 970 and 2475 years are used in the seismic analysis. The records used for the temporal analyses were ground motions that agree with a preliminary seismic hazard on the Moon. The results of temporal analyses reveal that shallow moonquakes with return periods greater than 475 years can lead to the loss of the global stability of the structure. Consequently, the findings imply that seismic loads have the potential to impose unacceptable demands on lunar structures constructed from in-situ materials like sulfur concrete. Hence, it is imperative to incorporate seismic considerations in the design process for developing resilient and long-term lunar habitats.

Lunar habitat↗
NASA NTRS1978

Use of a bubble tiltmeter as a horizontal seismometer

A bubble tiltmeter has been used as a horizontal seismometer. With the appropriate filters, the bubble system has good response for displacement over the passband of conventional seismometers (from about 10 Hz to 200 s), and for tilt from about 1 Hz to DC. The accuracy of the response is confirmed by comparing the filtered bubble output to conventional seismic instruments. The agreement between the filtered bubble records and broad band and short period conventional records is extremely good in every case. The small size, broad-band response, and lack of moving parts make the bubble ideal as an instrument for remote environments. In particular, the instrument seems ideal for the ocean bottom, land and marine boreholes and planetary missions.

Miller, W. F.↗
NASA NTRS1973

Intruder detection system

An intruder detection system is described. The system contains a transmitter which sends a frequency modulated and amplitude modulated signal to a remote receiver in response to a geophone detector which responds to seismic impulses created by the intruder. The signal makes it possible for an operator to determine the number of intruders and the manner of movement.

Lee, R. D.↗
NASA NTRS1976

Thermal movement of the regolith

High-frequency seismic events observed at the Apollo landing sites indicate that the regolith moves in response to diurnal variations of thermal stresses. While these events (thermal moonquakes) are observed by each of the Passive Seismic Experiment stations, the location of their sources was not possible until they were observed by the Lunar Surface Profiling Experiment (LSPE) array at the Apollo 17 site. Comparison of source locations with topographic features near the LSPE array indicate that thermal moonquakes are associated to some degree with large rocks and to a larger degree with craters. They are not associated with man-made disturbances of the lunar surface. It is suggested that thermal moonquakes are the seismic expression of a phenomenon that is actively degrading slopes on the lunar surface.

Duennebier, F.↗
NASA NTRS1979

Analysis of Lunar Seismic Signals: Determination of Instrumental Parameters and Seismic Velocity Distributions

Inverse filters were designed to correct the effect of instrumental response, coupling of the seismometer to the ground, and near surface structures. The least squares technique was used to determine the instrumental constants and the transfer functions of the long period lunar seismographs. The influence of noise and the results of these calculations are discussed.

Horvath, P.↗
NASA NTRS2020

The InSight APSS Data Return Anomaly: Development of an Automated Detection and Response Method

The Auxiliary Payload Sensor Suite (APSS), a collection of environmental sensors carried by the Interior exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander, is capable of measuring Martian air temperature, wind speed, atmospheric pressure, and local magnetic fields. After beginning Mars surface operations, the instrument experienced an anomaly that prevented it from returning science data. The anomaly affected not only the instrument, but also had impacts at the system level. APSS returned to normal operations, however the anomaly occurred again just several weeks later. This proved the need for a streamlined recovery response that would be adaptable to the operations planning cycle and workforce, that would limit the system-level impacts of the anomaly, and that would minimize the instrument downtime. The recovery response evolved from a ground-in-the-loop response to an onboard method for detecting occurrences of the anomaly and automatically recovering the instrument. Ultimately, the automated detection and response method reduced instrument downtime from days to hours and significantly minimized science data loss.

Mittal, Nimisha↗
NASA NTRS1985

Considerations of large scale impact and the early Earth

Bodies which have preserved portions of their earliest crust indicate that large scale impact cratering was an important process in early surface and upper crustal evolution. Large impact basins form the basic topographic, tectonic, and stratigraphic framework of the Moon and impact was responsible for the characteristics of the second order gravity field and upper crustal seismic properties. The Earth's crustal evolution during the first 800 my of its history is conjectural. The lack of a very early crust may indicate that thermal and mechanical instabilities resulting from intense mantle convection and/or bombardment inhibited crustal preservation. Whatever the case, the potential effects of large scale impact have to be considered in models of early Earth evolution. Preliminary models of the evolution of a large terrestrial impact basin was derived and discussed in detail.

Grieve, R. A. F.↗
NASA NTRS2012

Simplex GPS and InSAR Inversion Software

Changes in the shape of the Earth's surface can be routinely measured with precisions better than centimeters. Processes below the surface often drive these changes and as a result, investigators require models with inversion methods to characterize the sources. Simplex inverts any combination of GPS (global positioning system), UAVSAR (uninhabited aerial vehicle synthetic aperture radar), and InSAR (interferometric synthetic aperture radar) data simultaneously for elastic response from fault and fluid motions. It can be used to solve for multiple faults and parameters, all of which can be specified or allowed to vary. The software can be used to study long-term tectonic motions and the faults responsible for those motions, or can be used to invert for co-seismic slip from earthquakes. Solutions involving estimation of fault motion and changes in fluid reservoirs such as magma or water are possible. Any arbitrary number of faults or parameters can be considered. Simplex specifically solves for any of location, geometry, fault slip, and expansion/contraction of a single or multiple faults. It inverts GPS and InSAR data for elastic dislocations in a half-space. Slip parameters include strike slip, dip slip, and tensile dislocations. It includes a map interface for both setting up the models and viewing the results. Results, including faults, and observed, computed, and residual displacements, are output in text format, a map interface, and can be exported to KML. The software interfaces with the QuakeTables database allowing a user to select existing fault parameters or data. Simplex can be accessed through the QuakeSim portal graphical user interface or run from a UNIX command line.

Donnellan, Andrea↗