In my email of December 31, 2005, I was pessimistic about digitally =20 extending the low frequency response of a geophone to a value useful for te= leseisms.=20 However, I have been encouraged by my experiments on data recorded by J=F3n= =20 Fr=EDmann J=F3nsson of Iceland. Please inspect the volume file=20 =20 "060117.015700.hvtzlp Mb4.5 259km from Hvammstangi, Iceland (Inverse=20 Filtered): REYKJANES RIDGE"=20 =20 which I have submitted to the New PSN Earthquake Data Files list. This is a= =20 volume file consisting of two traces. The upper trace is the result of =20 applying "WQFilter.exe" to the data of the bottom trace. You will see that =20= inverse=20 filtering has brought out microseisms and the longer period components of t= he=20 event. I set the Long Period filter to extend the sensor period from 0.22=20 seconds to 4.0 seconds. =20 Bob McClureIn my email of December 31, 2005, I was pessimistic about digita= lly=20 extending the low frequency response of a geophone to a value useful for=20 teleseisms. However, I have been encouraged by my experiments=20 on data recorded by J=F3n Fr=EDmann J=F3nsson of Iceland. Please i= nspect the=20 volume file"060117.015700.hvtzlp Mb4.5 259km from Hvammstangi, Icelan= d=20 (Inverse Filtered): REYKJANES RIDGE"which I have submitted to the New PSN Earthquake Data Files list.=20= This=20 is a volume file consisting of two traces. The upper trace is the result of=20 applying "WQFilter.exe" to the data of the bottom trace. You will see that=20 inverse filtering has brought out microseisms and the longer period=20 components of the event. I set the Long Period filter to extend th= e=20 sensor period from 0.22 seconds to 4.0 seconds.Bob McClure