LabVIEW real-time seismic alert system
This Design Idea describes a real-time seismic alert system, which acquires seismic alert data from the European Mediterranean Seismological Center (EMSC) public web page using the “Data Socket connectivity” library in LabVIEW as part of a virtual instrument.
The Real Time Earthquake Information (RTEI) services operate with the support of the Laboratory for Detection and Geophysics seismic group (LDG) by compiling real time parametric data received by email and provided by 66 seismological networks. EMSC provides several services in the field of rapid information on the European-Mediterranean seismicity and significant earthquakes worldwide.
Figure 1 shows a simple LabVIEW program using Data Socket open, read and close function libraries (Figure 2) to acquire the worldwide seismic data from www.emsc-csem.org. The variant-to-data function (Figure 3) converts any data type to string, decimal, or any required type as per the selector “Type”.
Figure 1 LabVIEW program acquires seismic data from the URL and converts to String data for real-time display.
Figure 2 LabVIEW built-in function libraries for Data Socket open, read, and close
Figure 3 LabVIEW Variant to Data conversion function library
From the output string obtained from the variant function (which contains the messages like source parameters (origin time, epicenter location, focal depth, magnitude), phase pickings (station code, arrival times, phase type, amplitudes, and periods), etc., the important parameters required to alert the public, like date, place of occurrence, magnitude, intensity, altitude, time of occurrence, etc. can be extracted by LabVIEW string functions and displayed in a graphical user interface, with a threshold visual alarm indication as shown in Figure 4.
Figure 4 Virtual instrument real-time seismic alert system in LabVIEW front panel
Figure 5 shows the function panel diagram of the program implementation with “HTML Read” sub-VI as shown in Figure 1, and various string functions to extract the required field data from the several pages of HTML string data. By making use of the date and time stamp function, matching this information with the received data, and extracting the current occurrence, is the method implemented. To get the current Indian time, 5:30 has been added to the ISD timing obtained in the web data string. The string functions used are “Match String function” and “Split string”, with option fields for “offset” and “length” to get only the required data, like magnitude, depth, intensity, latitude, place, & origin. A threshold setting has been provided to make a visual warning signal in case the magnitude crosses a threshold level – 7.5, or any other user set value.
Figure 5 Virtual instrument real-time seismic alert system in LabVIEW function panel
Figure 6 The extracted data from the public Web page www.emsc-csem.org shows the various parameters of the real-time seismic information.
This design has been tested continuously for more than six months and found to be working well without any error, and it allows the public to be made aware of natural calamities. The LabVIEW program can be compiled into an executable to install in any PC, without needing LabVIEW to be installed. With LabVIEW, use of cellphone connectivity functions would allow data to be transmitted to a cellphone networked group.
Download the LabVIEW code here. (use Save As and remove the dummy .txt before saving)
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