- Why automatic attractive?
- large amount of seismic data ;
- if manually,it depends om experience of analyst;
- Quliaty can be obscured by several factors such as background and non-stationary noise from diverse sources;
- 该软件使用的方法为
STA-LTA(针对振幅突变识别很有效);
AMPA;
An autogressive AIC-based picking method ;
- 软件优点
- 适用于多平台;
- 可以处理大批量,不同文件格式的数据;
- 可用于microseismicity的震相拾取;
- 软件相关依赖
Scientific computing packages such as ObsPy,SciPy,NumPy,and Matplotlib
- 拾取精度对后续工作的影响
- tomographic inversion of active-source data(震相成像分析)
- HYPOCENTER LOCATION
- 作者思路:将前人拾取方法分为用于粗糙拾取( relatively imprecise)和精确拾取(precise)两种
- STA/LTA:naive version of the method has too broad range in parameter configuration;(可能需要大量统计实验对于不同距离范围的地震)
- direct use of an envelope function with a dynamic trigger level ;(Baer and Kradolfer,1987)
- higher-order statistic;(Saragiotis et al.,2002;Kuperkoch et al,.2010;Nippress et al.,2008)
- polarization approaches;(Montalbetti and Kanasewich,1970;Kurzon et al.,2014)
- local-maxima distribution(Panagiotakis et al.,2008)
- wavelet-based methods(Zhang et al.,2003)
- even pattern recognition methods(Tong,1995)
- neural networks(Dai andMacBeth,1995;Gentili and Michelini,2006)
- computer vision inspired methods(Joswig,1990)
- Autogressive models:the standard one named AR-AIC (建立背景噪声和到来震相的自回归模型):find the phase coming point that the locally stationary AR model attains the minimum value of the Akaike information criterion.(达到某个标准的最小值时);:该方法拾取较精确,但由于计算比较强烈建议用于已经有过初步估计的初动拾取工作中;
- 解决信噪比低的信号的方案
AMPA algorithm(Adaptive Muti-Band Picking Algorithm):related article-Alvarez et al.,2013
It applied a serises of filtering stages to the input signal in order to 减弱环境噪声并加强震相的到来。
- step1:using filter bank to eatimate the signal envelope and equalize (补偿) noise for each subband.filter band
- the resultant envelope is filterd by a use of set of filters,each one designed different length in order to enhance the phase arrival and lower emergent noised.
- 软件方法支撑
STA/LTA 和AMPA picking algorithm 为主 ;AIC为辅;
- 软件框架
- apasvo-gui:交互型界面,允许用户手动改值;
- apasvo-detector:允许使用命令行来计算;有批处理和监督模式两种选择模式,监督用来交互型地判断是否是满意的拾取,是否接受。批处理则在处理过程中不过问。
- apasvo-generator:允许使用命令行来产生地震波轨迹,并允许其中有背景噪声;