Analyses of MAGSAT tracks crossing the study region in the Indian Ocean

Progress in software development and in preliminary analysis of MAGSAT tracks crossing the Indian Ocean is reported. Tracks crossing the Java Trench, Broken Ridge, the Southeast Indian Ridge, and the Ninetyeast Ridge show that magnetic anomalies correlate with some of these features. Preliminary study of anomaly profiles indicates that tracks of anomaly data (the observations minus a core field model) have a power spectrum decreasing as the inverse square of the spatial frequency. An apparent noise floor of about one to two gammas rms is reached at wavelengths of about 360 km, corresponding to approximately 10 samples of the decimated Investigator tape data at a sampling rate of approximately 4.9 sec/sample

MAGSAT anomaly profiles of the eastern Indian Ocean

Ground tracks from SEASAT were used in an effort to develop qualititative relationships between the gravity field and MAGSAT magnetic anomalies in the eastern Indian Ocean. Investigation of data quality led to analyses of the average value (over 80 vector data points, or approximately 36 km intervals) and of the standard deviation of this average, as a mean of identifying noisy portions of the data. It was discovered that the plots of the average value minus the individual (measured) point value are most useful for identifying noisy areas and data spikes. Spectrum analysis using edited (spikes removed) data show that the noise floor is less than 1 nT and the slope of the spectrum in the region of wavelengths between 1200 km and 250 km is approximately -3. Consequently the estimated resolution limit improved from approximately 360 km to approximately 250 km

Analyzing the Broken Ridge area of the Indian Ocean using magnetic and gravity anomaly maps and geoid undulation and bathymetry data

A higher resolution anomaly map of the Broken Ridge area (2 degree dipole spacing) was produced and reduced to the pole using quiet time data for this area. The map was compared with equally scaled maps of gravity anomaly, geoid undulation, and bathymetry. The ESMAP results were compared with a NASA MAGSAT map derived by averaging data in two-degree bins. A survey simulation was developed to model the accuracy of MAGSAT anomaly maps as a function of satellite altitude, instrument noise level, external noise model, and crustal anomaly field model. A preliminary analysis of the geophysical structure of Broken Ridge is presented and unresolved questions are listed

MAGSAT investigation of crustal magnetic anomalies in the eastern Indian Ocean

Crustal magnetic anomalies in a region of the eastern Indian Ocean were studied using data from NASA's MAGSAT mission. The investigation region (0 deg to 50 deg South, 75 to 125 deg East) contains several important tectonic features, including the Broken Ridge, Java Trench, Ninetyeast Ridge, and Southeast Indian Ridge. A large positive magnetic anomaly is associated with the Broken Ridge and smaller positive anomalies correlate with the Ninetyeast Ridge and western Australia. Individual profiles of scalar data (computed from vector components) were considered to determine the overall data quality and resolution capability. A set of MAGSAT ""Quiet-Time'' data was used to compute an equivalent source crustal magnetic anomaly map of the study region. Maps of crustal magnetization and magnetic susceptibility were computed from the equivalent source dipoles. Gravity data were used to help interpretation, and a map of the ratio of magnetization to density contrasts was computed using Poisson's relation. The results are consistent with the hypothesis of induced magnetization of a crustal layer having varying thickness and composition

Investigating tectonic and bathymetric features of the Indian Ocean using MAGSAT magnetic anomaly data

MAGSAT Investigator-B tapes were preprocessed by (1) removing all data points with obvious erroneous values and location errors; (2) removing smaller spikes (typically 15 nT or more), and deleting data tracks with fewer than 20 points; and (3) removing a linear trend from each track. The remaining data were recorded on tape for use by the equivalent source mapping (ESMAP) program which uses a least squares algorithm to fit the magnetization parameter of the grid of equivalent source dipoles in the crust to satellite data acquired at different times and locations. ESMAP was implemented on the TASC computing system and modified to read preprocessed MAGSAT tapes and interface with TASC plotting software. Some verification of the software was accomplished. Gridded 1-degree mean values of gravity anomaly and sea surface undulation computed from SEASAT radar altimeter were obtained and brought on line

GPS-aided gravimetry at 30 km altitude from a balloon-borne platform

A balloon-borne experiment, flown at 30 km altitude over New Mexico, was used to test dynamic differential Global Positioning System (GPS) tracking in support of gravimetry at high-altitudes. The experiment package contained a gravimeter (Vibrating String Accelerometer), a full complement of inertial instruments, a TI-4100 GPS receiver and a radar transponder. The flight was supported by two GPS receivers on the ground near the flight path. From the 8 hour flight, about a forty minute period was selected for analysis. Differential GPS phase measurements were used to estimate changes in position over the sample time interval, or average velocity. In addition to average velocity, differential positions and numerical averages of acceleration were obtained in three components. Gravitational acceleration was estimated by correcting for accelerations due to translational motion, ignoring all rotational effects

Bathymetric and tectonics of Indian Ocean using MAGSAT data

The quality of the MAGSAT data was assessed, especially the characterization of spikes. The spectral passbands of significance to geophysical analysis were analyzed, including computations of spectral coherence between nearby repeating satellite tracks. A spectrum modeling effort was begun which is designed to show the effect of spacecraft attitude on the observability of magnetic anomalies. The data obtained is to be used to compute crustal anomaly maps by modeling the equivalent dipoles in the project area

Embodied Healing: Clinician’s Perspectives on Somatic Interventions for Trauma

The focus of this research was to gain insight into the perspectives of clinicians on their experiences employing Sensorimotor Psychotherapy with clients who have experienced trauma. The conceptual framework used for this research project was based on modern attachment theory and interpersonal biology. To explore the research topic, qualitative research methods were employed to gather the experiences of mental health practitioners who currently use Sensorimotor Psychotherapy, examining why they view this model as an effective intervention for the treatment of trauma. The sample consisted of four licensed mental health professionals who currently use Sensorimotor Psychotherapy with clients who have experienced trauma. All participants had completed the Level II Trauma Training for Sensorimotor Psychotherapy and currently work in private practice. Data was collected through the use of semi-structured, in- person interviews, and analyzed through the use of grounded theory techniques. After analysis of the transcripts, three main themes emerged: 1) Importance of creating safety within the therapeutic relationship, 2) Use of mindfulness and somatic resourcing, and 3) Use of experiential practices. Strengths of this study include the gathering of the nuanced perspectives of clinicians working in the field with clients who have experienced trauma and the use of in- depth interviews that allowed the researcher to capture the voices of clinicians in their own words with a richness and depth unavailable with quantitative data. Limitations of this study include the small sample size, potential participant bias towards somatically focused therapies, and the lack of varied practice settings among participants

Embodied Healing: Clinician\u27s Perspectives on Somatic Interventions for Trauma

The focus of this research was to gain insight into the perspectives of clinicians on their experiences employing Sensorimotor Psychotherapy with clients who have experienced trauma. The conceptual framework used for this research project was based on modern attachment theory and interpersonal biology. To explore the research topic, qualitative research methods were employed to gather the experiences of mental health practitioners who currently use Sensorimotor Psychotherapy, examining why they view this model as an effective intervention for the treatment of trauma. The sample consisted of four licensed mental health professionals who currently use Sensorimotor Psychotherapy with clients who have experienced trauma. All participants had completed the Level II Trauma Training for Sensorimotor Psychotherapy and currently work in private practice. Data was collected through the use of semi-structured, in-person interviews, and analyzed through the use of grounded theory techniques. After analysis of the transcripts, three main themes emerged: 1) Importance of creating safety within the therapeutic relationship, 2) Use of mindfulness and somatic resourcing, and 3) Use of experiential practices. Strengths of this study include the gathering of the nuanced perspectives of clinicians working in the field with clients who have experienced trauma and the use of in-depth interviews that allowed the researcher to capture the voices of clinicians in their own words with a richness and depth unavailable with quantitative data. Limitations of this study include the small sample size, potential participant bias towards somatically focused therapies, and the lack of varied practice settings among participants

Investigating tectonic and bathymetric features of the Indian Ocean using MAGSAT magnetic anomaly data

An equivalent source anomaly map and a map of the relative magnetization for the investigation region were produced. Gravimetry, bathymetry, and MAGSAT anomaly maps were contoured in pseudocolor displays. Finally, an autoregressive spectrum estimation technique was verified with synthetic data and shown to be capable of resolving exponential power spectra using small samples of data. Interpretations were made regarding the relationship between MAGSAT data spectra and crustal anomaly spectra