How to refine earthquake data downloaded from website?

Are you engineer? or seismologist? or designer? or even you may be a person who have interest on earthquake and its mechanism, time series etc. If you are worry about how you can get and process earthquake data, Here is a complete solution for how you can refine raw earthquake data. Just follow few steps then you can have clear view of earthquake time series.

Step 1: Data download

If you have already data sets of some earthquakes they may be in format like below which had taken in EW, NS and UD directions. Files are named as (station name+date+time ). 

OKN0109805040830.ew

OKN0109805040830.ns

OKN0109805040830.ud       (These files recorded in OKN010 station at 1998/05/04 08:30)

For Earthquake in and near Japan, NIED having 1880 stations records data. To download raw data from NIED click below.

KNET/KIKNET Data Download

 To download you have to register to the site but do not worry its free :) . 

data sets seems like this in website. you can click at right bottom "Download All channels data"

Those data are in zipped folder just unzip them all and save in one folder.

Step 2: Rename files

Now you have three files with extensions *.ew, *.ns, and *.ud. those file names just change in to 1.ew, 2.ns and 3.ud .

Step 3: Download executable programme

You need to download one executable program, that can be downloaded from this link click HERE .

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How to find out epicentre of earthquake?

You may confuse that many agencies locate different points for the epicentre of same earthquake, it may happens because of recording stations around the possible location.

Here is one example of one method to find out epicentre.

To figure out just where that earthquake happened, you need to look at your seismogram and you need to know what at least two other seismographs recorded for the same earthquake. You will also need a map of the world, a ruler, a pencil, and a compass for drawing circles on the map.

Here's an example of a seismogram:

FIGURE 1 - OUR TYPICAL SEISMOGRAM FROM BEFORE,

 THIS TIME MARKED FOR THIS EXERCISE (FROM BOLT, 1978).

One minute intervals are marked by the small lines printed just above the squiggles made by the seismic waves (the time may be marked differently on some seismographs). The distance between the begining of the first P wave and First S wave tell you how many seconds the waves are apart. This number will be used to tell you how far your seismograph is from the epicenter of the earthquake.

Finding the Distance to the Epicenter and the Earthquake's Magnitude 1.     Measure the distance between the first P wave and the first S wave. In this case, the first P and S waves are 24 seconds apart. 2.     Find the point for 24 seconds on the left side of the chart below and mark that point. According to the chart, this earthquake's epicenter was 215 kilometers away. 3.     Measure the amplitude of the strongest wave. The amplitude is the height (on paper) of the strongest wave. On this seismogram, the amplitude is 23 millimeters. Find 23 millimeters on the right side of the chart and mark that point. 4.     Place a ruler (or straight edge) on the chart between the points you marked for the distance to the epicenter and the amplitude. The point where your ruler crosses the middle line on the chart marks the magnitude (strength) of the earthquake. This earthquake had a magnitude of 5.0. FIGURE 2 - USE THE AMPLITUDE TO DERIVE THE MAGNITUDE OF THE EARTHQUAKE,  AND THE DISTANCE FROM THE EARTHQUAKE TO THE STATION. (FROM BOLT, 1978)

Finding the Epicenter

You have just figured out how far your seismograph is from the epicenter and how strong the earthquake was, but you still don't know exactly where the earthquake occurred. This is where the compass, the map, and the other seismograph records come in.

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