عنوان

Crustal and upper mantle velocity structure determination using inversion methods

شماره

TLpq303843213

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Crustal and upper mantle velocity structure determination using inversion methods

نام عام مواد

[Thesis]

نام نخستين پديدآور

A. Ibenbrahim

نام ساير پديدآوران

J. F. Ni

نام ناشر، پخش کننده و غيره

New Mexico State University

تاریخ نشرو بخش و غیره

1990

نام خاص و کميت اثر

216

جزئيات پايان نامه و نوع درجه آن

Ph.D.

کسي که مدرک را اعطا کرده

New Mexico State University

امتياز متن

1990

متن يادداشت

In the first part of this dissertation an iterative source equalization method was introduced to extend previous methods which approximated the vertical receiver function by a delta function, and used this approximation to remove the source effects from seismograms. For short-period data the above approximation is not sufficient, instead we estimate the entire vertical receiver function and use it to obtain a better approximation of the source effects. In the second part of this dissertation the iterative method of Part I was applied to invert for the shear-wave receiver structure beneath the Albuquerque station. The results reveal the existence of an upper crustal low shear-wave velocity zone (LVZ). This LVZ can be attributed to the presence of either water or magma bodies. The lower crust is also characterized by a LVZ that extends from a 20-34 km depth. We suggest that this LVZ is due to magma bodies within a 26-30 km depth range. Our results indicate that the Moho is at a 46 km depth and consists of a 4 km transitional zone. In the third part of this dissertation P- and S-wave travel time data were used to simultaneously invert for velocity structures and hypocenters beneath the Tarbela seismic network, which is situated in the western Hazara Arc, Pakistan. We find that the eastern part of the Hazara-Kashmir Syntaxis is underlain by a low velocity zone which we interpreted as a former foreland basin covered by late-stage southeasterly directed thrust sheets. North of the Hazara Thrust Zone (HTZ), the velocity structures indicate that the underthrusting Indian Plate dips gently to the northeast with an increased slope of 5 to 8 until it reaches the NW trending Indus-Kohistan Seismic Zone (IKSZ). Along the IKSZ the Indian Plate bends more steeply to the northeast. The IKSZ appears to consist of two distinct seismic zones separated by a 4 km thick aseismic region. This aseismic zone may indicate an upper crustal detachment. The lower IKSZ is wedge shaped and may represent the leading edge of a southwestward directed basement slab which has not yet ruptured the surface.

موضوع مستند نشده

Earth sciences

موضوع مستند نشده

Geophysics

موضوع مستند نشده

Peshawar Basin

موضوع مستند نشده

Rio Grande Rift

موضوع مستند نشده

velocity structure

مستند نام اشخاص تاييد نشده

A. Ibenbrahim

مستند نام اشخاص تاييد نشده

J. F. Ni

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y