عنوان

Lateral variation of velocity and attenuation structure in the Middle East from surface waves and Lg coda

Number

TLpq304364839

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Lateral variation of velocity and attenuation structure in the Middle East from surface waves and Lg coda

General Material Designation

[Thesis]

First Statement of Responsibility

L. Cong

Subsequent Statement of Responsibility

B. J. Mitchell

Name of Publisher, Distributor, etc.

Saint Louis University

Date of Publication, Distribution, etc.

1997

Specific Material Designation and Extent of Item

243

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Saint Louis University

Text preceding or following the note

1997

Text of Note

Rayleigh wave phase velocity, group velocity, and attenuation data were inverted for shear velocity and shear-wave usdQ\ (Q\sb{\mu})usd structure in the Middle East using two- and single-station methods. Results indicate that both velocity and usdQ\sb{\mu}usd values vary regionally and with depth. At upper-mantle depths, shear velocities are roughly the same for different portions of the region. In the crust, shear velocities are highest in the Arabian Peninsula (Region 3), lowest in the Black Sea, the Caspian Sea, and adjacent areas (Region 2), and intermediate in the Turkish and Iranian Plateaus (Region 1). The average shear velocities for the uppermost 10 km are 3.21, 2.85, and 3.39 km/s for Regions 1, 2, and 3, respectively. Average usdQ\sb{\mu}usd for the crust is 55, 75, 150 in Regions 1, 2, and 3, respectively. These values are much lower than those obtained for other regions in the world, but can be explained by high heat flow and recent tectonic activity in and around the Middle East. High-frequency usdL\sb{g}usd coda attenuation was also used to investigate the efficiency of wave propagation. The stacked spectral ratio method was used to analyze the data, and a back-projection method was then employed to map the regional variations of usdL\sb{g}usd coda Q. The resulting tomographic map of usdL\sb{g}usd coda Q at 1 Hz usd(Q\sb0)usd shows a variation in the range 350-450 in the Arabian peninsula. These values are larger than those (150-300) found in the northern portion of the Middle East, where young faulting and deformation are currently occurring. The lowest value of usdQ\sb0usd occurs in west Anatolia where extremely high heat flow has been measured.

Earth sciences

Geophysics

shear velocity

velocity attenuation

B. J. Mitchell

L. Cong

Electronic name

p

[Thesis]

276903

a

Y