【摘要】：地震動衰減關(guān)系是工程地震研究的核心,簡化了地震的震源、地震波的傳播途徑以及局部場地條件三方面因素對地震動特性的影響,可以為重大工程結(jié)構(gòu)抗震設(shè)計工作提供合理的抗震設(shè)防參數(shù)。目前,在美國西部和日本等強震記錄豐富的國家和地區(qū),主要利用強地震動觀測數(shù)據(jù)統(tǒng)計回歸的方法建立經(jīng)驗性衰減關(guān)系。然而,我國大陸強震記錄相對較少,如何建立強地震動衰減關(guān)系一直是工程地震領(lǐng)域的研究熱點。另一方面,“十一五”之后,隨著中國大陸數(shù)字地震觀測技術(shù)和地震觀測能力的不斷發(fā)展進步,地震監(jiān)測能力得到了大幅度提高,國家及區(qū)域?qū)掝l帶數(shù)字地震臺網(wǎng)都積累了大量的數(shù)字地震波形資料。本文借助寬頻帶數(shù)字地震監(jiān)測臺網(wǎng)小震記錄,估計東南沿海地區(qū)地震動。論文主要完成了以下工作:1.在東南沿海地區(qū)(北緯22°-29°,東經(jīng)109°-120°),收集到廣東和福建區(qū)域數(shù)字地震觀測臺網(wǎng)和國家數(shù)字測震臺網(wǎng)數(shù)據(jù)備份中心在1999年到2013年間記錄到的72次小震(Mw=3.5-4.5、震源深度≤30km)的1274條記錄。2.將收集到的測震數(shù)據(jù)按照地震震中位置的不同劃分為海域、陸域和全部數(shù)據(jù)三組,以傅里葉幅值譜的包絡(luò)線為目標(biāo)曲線,借助微遺傳算法,反演5個區(qū)域震源和地殼介質(zhì)參數(shù)(應(yīng)力降Δσ、品質(zhì)因子參數(shù)Q0和η、幾何衰減參數(shù)R1和R2),三組數(shù)據(jù)反演結(jié)果差別不大。3.在建立強地震動衰減關(guān)系的過程中,將近地表高頻截止項用Kappa濾波器表達,分別采用Original Kappa和Fixed-Kappa兩種方法計算測震數(shù)據(jù)的Kappa值。討論兩種Kappa值與矩震級、震源深度和震中距的關(guān)系。研究表明,Kappa值與震級大小和震源深度之間沒有相關(guān)性,與距離相關(guān)。4.將反演的區(qū)域參數(shù)和兩個Kappa值分別代入計算程序,建立相應(yīng)的強地震動衰減關(guān)系。與東南沿海地區(qū)有限的強震觀測數(shù)據(jù)比較,驗證本文衰減關(guān)系的可靠性。5.結(jié)合本文反演的區(qū)域震源與地殼介質(zhì)參數(shù),以及用測震數(shù)據(jù)得到的Kappa值,借助有限斷層混合震源模型,合成了九龍江斷裂6.0級地震中5個試算點的地震動。與經(jīng)驗性給出區(qū)域參數(shù)得到的試算點反應(yīng)譜比較,本文結(jié)果偏高,原因是反演參數(shù)值比經(jīng)驗性給出的數(shù)值大;與本文建立的衰減關(guān)系得到的試算點反應(yīng)譜比較,短周期接近,有限斷層混合震源模型結(jié)果表現(xiàn)出上盤效應(yīng)和方向性效應(yīng)。
[Abstract]:The attenuation relation of ground motion is the core of engineering seismic research. It simplifies the influence of earthquake source, propagation path of seismic wave and local site conditions on the characteristics of earthquake motion. It can provide reasonable seismic fortification parameters for seismic design of major engineering structures. At present, in countries and regions with abundant records of strong earthquakes in the western United States and Japan, the empirical attenuation relationship is established by means of statistical regression method of strong ground motion observation data. However, there are relatively few records of strong earthquakes in the mainland of China. How to establish the attenuation relationship of strong ground motion has been a hot topic in the field of engineering earthquake. On the other hand, after the 11th Five-Year Plan, with the continuous development and progress of digital seismic observation technology and seismic observation capability in the mainland of China, the ability of seismic monitoring has been greatly improved. National and regional broadband digital seismic networks have accumulated a large number of digital seismic waveform data. In this paper, the ground motion in southeast coastal area is estimated by using the small earthquake records of broadband digital seismic monitoring network. The main work of this paper is as follows: 1. In the southeast coastal area (latitude 22 擄-29 擄N and longitude 109 擄-120 擄E), 1274 records of 72 small earthquakes (Mw=3.5-4.5, focal depth 鈮，

本文編號：2273997