A case history: 3-D gravity modeling using hexahedral element in Kinigi geothermal field, Rwanda

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Jean d’Amour Uwiduhaye ◽  
Hideki Mizunaga ◽  
Hakim Saibi
Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. ID59-ID71 ◽  
Author(s):  
Kyle Basler-Reeder ◽  
John Louie ◽  
Satish Pullammanappallil ◽  
Graham Kent

Joint seismic and gravity analyses of the San Emidio geothermal field in the northwest Basin and Range province of Nevada demonstrate that joint optimization changes interpretation outcomes. The prior 0.3–0.5 km deep basin interpretation gives way to a deeper than 1.3 km basin model. Kirchoff prestack depth migrations reveal that joint optimization ameliorates shallow velocity artifacts, flattening antiformal reflectors that could have been interpreted as folds. Furthermore, joint optimization provides a clearer picture of the rangefront fault by increasing the depth of constrained velocities, which improves reflector coherency at depth. This technique provides new insight when applied to existing data sets and could replace the existing strategy of forward modeling to match gravity data. We have achieved stable joint optimization through simulated annealing, a global optimization algorithm that does not require an accurate initial model. Balancing the combined seismic-gravity objective function is accomplished by a new approach based on analysis of Pareto charts. Gravity modeling uses an efficient convolution model, and the basis of seismic modeling is the highly efficient Vidale eikonal equation traveltime generation technique. Synthetic tests found that joint optimization improves velocity model accuracy and provides velocity control below the deepest headwave raypath. Restricted offset-range migration analysis provides insights into precritical and gradient reflections in the data set.


2015 ◽  
Vol 10 (2) ◽  
pp. 32-45
Author(s):  
Asep Sugianto ◽  
Tony Rahardinata

Daerah panas bumi Dolok Marawa merupakan salah satu daerah prospek panas bumi di Sumatera bagian utara. Daerah panas bumi tersebut berada pada zona patahan Sumatera dengan manifestasi permukaan berupa sekelompok mata air panas yang memiliki temperatur antara 37o C hingga 65 o C. Serangkaian survei gaya berat telah dilakukan di daerah ini pada tahun 2006 dan 2015. Sebanyak 257 data gaya berat telah diukur dari daerah ini, dengan cakupan luas pengukuran sekitar 16 km x 13 km. Penelitian ini bertujuan untuk mengetahui distribusi densitas batuan melalui pemodelan 3D pada data gaya berat dengan menggunakan perangkat lunak Grablox. Hasil pemodelan memperlihatkan suatu blok berdensitas rendah yang bentuknya berarah baratlaut-tenggara dan berimpit dengan zona patahan. Densitas batuan rendah tersebut bernilai sekitar 2,4 g/cm 3 dan dianggap sebagai batuan rekahan yang mengisi zona patahan. Hasil pemodelan juga memperlihatkan suatu blok berdensitas tinggi di bawah bukit Dolok Bahtopu. Blok densitas tinggi ini diinterpretasikan sebagai suatu tubuh intrusi andesitik dan mungkin bertindaksebagai sumber panas bagi sistem panas bumi Dolok Marawa. 


2020 ◽  
Vol 29 (4) ◽  
pp. 685-690
Author(s):  
C. S. Vanaja ◽  
Miriam Soni Abigail

Purpose Misophonia is a sound tolerance disorder condition in certain sounds that trigger intense emotional or physiological responses. While some persons may experience misophonia, a few patients suffer from misophonia. However, there is a dearth of literature on audiological assessment and management of persons with misophonia. The purpose of this report is to discuss the assessment of misophonia and highlight the management option that helped a patient with misophonia. Method A case study of a 26-year-old woman with the complaint of decreased tolerance to specific sounds affecting quality of life is reported. Audiological assessment differentiated misophonia from hyperacusis. Management included retraining counseling as well as desensitization and habituation therapy based on the principles described by P. J. Jastreboff and Jastreboff (2014). A misophonia questionnaire was administered at regular intervals to monitor the effectiveness of therapy. Results A detailed case history and audiological evaluations including pure-tone audiogram and Johnson Hyperacusis Index revealed the presence of misophonia. The patient benefitted from intervention, and the scores of the misophonia questionnaire indicated a decrease in the severity of the problem. Conclusions It is important to differentially diagnose misophonia and hyperacusis in persons with sound tolerance disorders. Retraining counseling as well as desensitization and habituation therapy can help patients who suffer from misophonia.


2020 ◽  
pp. 1-5
Author(s):  
David Luterman

Purpose The purpose of this article is to present a client-centered model of counseling that integrates information and personal adjustment counseling. Research has indicated that audiologists are more comfortable with counseling that is information based than with personal adjustment counseling. The prevailing model of diagnosis appears to be the medical model in which, first, a case history is taken, then testing and, finally, counseling. This model lends itself to audiologist as expert and the counseling as a separate entity based on information and advice. Further research has indicated parents retain little of the information provided in the initial examination because of their heightened emotions. This article presents a client-centered model of diagnosis in which information is provided within an emotionally safe context, enabling the parents to express their feelings and have the ability to control the flow of information. The ultimate purpose of a client-centered model is to empower parents by making them active participants in the diagnostic process rather than passive recipients. Conclusion The client-centered model has wide implications for the diagnostic process as well as for the training of students.


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