Lateral variations of Pn propagation in Italy: Evidence for a high attenuation zone beneath the Apennines
Lateral variations of Pn propagation in Italy: Evidence for a high attenuation zone beneath the Apennines
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意大利 Pn 传播的横向变化：亚平宁山脉下方高衰减区的证据
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
M. Barazangi
中科院分区：
文献类型：
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作者：
G. Mele;A. Rovelli;D. Seber;M. Barazangi
本文利用意大利地震台网40个台站记录的Pn震相资料，用频谱比技术估算了意大利半岛及亚得里亚海附近地区上地幔的Q结构。共分析了344个数字波形，从22个地震，发生在300至1600公里的距离。计算出的表观Q值分为两类：Q > 800的特点是亚得里亚海一侧的意大利半岛，表明亚得里亚海岩石圈是非常有效的传播Pn相位通过最上层地幔; Q < 600的特点是最上层地幔下面的亚平宁山脉和意大利，表明不太有效的波传播。在亚平宁山脉之下的浅部，软流圈地幔物质的存在可以解释观测到的Q。
Pn phases recorded by 40 stations of the Italian seismic network are analyzed using the spectral ratio technique to estimate the Q structure of the uppermost mantle beneath the Italian peninsula and nearby Adriatic Sea. A total of 344 digital waveforms are analyzed from 22 earthquakes that occurred within distances of 300 to 1600 km. The calculated apparent Q values are grouped into two categories: Q > 800 characterizes the Adriatic side of the Italian peninsula, indicating that the Adriatic lithosphere is very efficient in propagating Pn phases through the uppermost mantle; Q < 600 characterizes the uppermost mantle beneath the Apennines and western Italy, indicating less efficient wave propagation. The presence of asthenospheric mantle material at shallow depths beneath the Apennines can explain the observed Q.