how to pick seismogram

I hope your day run well because today you will learn about picking seismogram. Picking is the main part of seismogram because if we can't pick seismogram. we will be useless to have seismogram. Picking here is to determine which one the P wave, S wave and also surface wave. if we can determine it, we will be able determining the epicenter of earthquake by using single event determination method or three balls method.

Before that you must have seisgram2K program which write by Anthony Lomax. this program is to display the seismograms data. You can visit this web site, seisgram2K. Substantively, you can display seismograms by other programs, such as JISView, gFORTRAN or mathlab. but here we use seisgram2K.

Seisgram2K can work under java application. so if your computer doesn't have java application this program can't work. you can visit this website for getting java.

I hope you don't get any problem in installing seisgram2K.

now we get going to run seisgram2K. this is the basic display of seisgram2K,

then open your seismograms data that you get from BMKG. if you still don't have seismograms, visit how to get seismograms from BMKG.
Open seismogram by clicking,
FILE > OPEN FILE.. > click your seismograms file > OPEN > OPEN(again)

here, the display of Seismogram, guys. every seismometer will be displayed by seisgram2K. you have to determine seismometers which catch event and not because not all of seismometer catches earthquake event.

then, this is time for picking seismogram, guys. you have to remember how the wave of earthquake runs in the ground. the first wave that catch by the seismometer is P wave because this wave is the fastest wave and then the following wave is S wave which sometimes has greater amplitude than P wave. the last wave is surface wave which has lowest velocity but have greatest amplitude. Ya..this wave makes hazard disaster for building. it can make every building collapse.

To pick wave from seisgram2K, click "Pick" tool, then select the the wave which you think as P wave or S wave. Yes...this method examines the seismologist in interpreting earthquake wave.

before we talk further about how to become good interpreter. first we learn the manual picking of seisgram. lets see the tools that I give red ellipse. first, choose P in the darker box to pick P wave or S to pick S wave. then the left and right side of it, you see some tools.

e : for unsure/unclear P or S wave that you select
i : for sure/clear P or S wave that you select

c : for compressive wave that shows by "hill" curve in first P or S wave arrival, like the signal that I give white ellipse.

d : for dilatation wave that shows by "valley" curve in first P or S wave arrival , like the signal that I give yellow ellipse.

after you have picked them, you can get travel time(Ts-Tp) and amplitude(Amp) in the bottom box with green letter. then by converting travel time with velocity model of research field you can get epicenter.

here, I would like to thank for Pak Nugroho, Kasi BMKG Tretes, who is patient and helpful. mbak ana and mbak novi, as our Tutor in BMKG, who are very kind and funny. and mas denni who gives much knowledge and skill. and also, Boss Saifuddin Kafi , as a great teammate, thanks for every thing and if I still have debt, don't be shy to collect to me. hehehe....

wish you get the usefulness from my blog.
any quetions, comment please. thanks