Earthquake Seismograph Analog as Earthquake Instrumentation
|Figure 1. Seismic Waves|
Let's start from the Aceh provincial boundary. The province of Aceh is an area located between 2º - 6º NL and 95º - 98º East. The westernmost area of Indonesia is surrounded by territorial boundaries, namely the north bordering the Malacca Strait, the southern part bordering North Sumatra, the east bordering the Malacca Strait, and the west bordering the Indonesian Sea.
Aceh is an area that experienced the worst earthquake in 2004 accompanied by a tsunami. The resulting strength reached 9.3 on the Ricther scale, which killed at least 250,000 people in countries in Asia and Africa. This happened due to the fault of the Sumatra fault that stretched from the Andaman Sea to South Sumatra. Aceh is located on the Indo-Australian plate and the Eurasian Plate and on the Mediterranean circum (Mulyatno, 2008).
The Indonesian archipelago is located between 6º NL to 11º E and 95º E to 141º E. Indonesia is located between two oceans and continents namely the Pacific Ocean and the Indian Ocean and the Continent of Asia and Australia.
Indonesia is a meeting area of 3 large tectonic plates, namely the Indo-Australian plate, Eurasian plate and the Pacific plate. The Indo-Australian Plate collides with the Eurasian plate off the coast of Sumatra, Java and Nusatenggara, while with the Pacific in northern Irian and northern Maluku.
Around the location of this plate meeting the accumulation of collision energy is collected to a point where the earth's layer is no longer able to hold the pile of energy so that it releases in the form of an earthquake (Erstayudha, 2009).
To be able to record and measure ground vibrations due to the earthquake continuously, so that the time of the earthquake, as well as knowing the strength of the earthquake and the location of the earthquake can be used an instrument that is Earthquake Seismograph.
General History of BMKG (BADAN METEOROLOGI, KLIMATOLOGI, DAN GEOFISIKA)The history of meteorological and geophysical observations in Indonesia began in 1841 beginning with observations made individually by Dr. Onnen, Head of the Hospital in Bogor. Year by year its activities are developing in accordance with the increasing need for data from weather and geophysical observations.
In 1879 a total of 74 observation stations were built on the rain gauge. In 1902 observations of the earth's magnetic field were moved from Jakarta to Bogor. Earthquake observation began in 1908 with the installation of a horizontal component of the Wiechert Earthquake Seismograph in Jakarta, while the installation of a vertical component was carried out in 1928. In 1912 a reorganization of meteorological observations was made by adding a secondary network. While meteorological services began to be used for lighting in 1930.
During the Japanese occupation between 1942 and 1945, the name of the meteorology and geophysics agency was changed to Kisho Kauso Kusho. After the proclamation of Indonesian independence in 1945, the agency was split into two: In Yogyakarta a Meteorological Bureau was formed within the Supreme Headquarters of the Indonesian People's Army specifically to serve the interests of the Air Force.
In Jakarta the Bureau of Meteorology and Geophysics was formed, under the Ministry of Public Works and Energy. On July 21, 1947 the Meteorology and Geophysics Service was taken over by the Dutch Government and its name was changed to Meteorologisch en Geofisiche Dienst.
Meanwhile, there is also the Meteorology and Geophysics Office maintained by the Government of the Republic of Indonesia, the agency's position on Jl. Gondangdia, Jakarta.
In 1949, after the surrender of the sovereignty of the Republic of Indonesia from the Netherlands, Meteorologisch en Geofisiche Dienst was changed to the Bureau of Meteorology and Geophysics under the Ministry of Transportation and Public Works.
Furthermore, in 1950 Indonesia officially entered as a member of the World Meteorological Organization (World Meteorological Organization or WMO) and the Head of the Meteorology and Geophysics Office became the Permanent Representative of Indonesia with WMO.
In 1955 the Meteorology and Geophysics Service was renamed the Meteorology and Geophysics Agency under the Department of Transportation, and in 1960 it was renamed the Meteorology and Geophysics Office under the Department of Air Transportation.
In 1965, the name was changed to the Directorate of Meteorology and Geophysics, his position remained under the Department of Air Transportation. In 1972, the Directorate of Meteorology and Geophysics was renamed the Center for Meteorology and Geophysics, an echelon II institution under the Department of Transportation, and in 1980 its status was upgraded to an echelon I-level agency under the name Meteorology and Geophysics, with a permanent position in the under the Department of Transportation.
In 2002, with Presidential Decree No. 46 and 48 of 2002, the organizational structure was changed to Non-Departmental Government Institutions (LPND) with the permanent name Meteorology and Geophysics Agency. Finally, through Presidential Regulation No. 61/2008, the Meteorology and Geophysics Agency was renamed the Badan Meteoroloi, Klimatologi and Geofisika (BMKG) with permanent status as Non-Departmental Government Institutions. On October 1, 2009 Law of the Republic of Indonesia Number 31 of 2009 concerning Meteorology, Climatology and Geophysics was ratified by the President of the Republic of Indonesia, Susilo Bambang Yudhoyono.
History of BMKG Banda AcehThe Banda Aceh Meteorology, Climatology and Geophysics Agency was established on 1979 which is located in the Mata Ie area, Darul Imarah sub-district, Aceh Besar. The Ie Banda Aceh Geophysics Station is one of the agencies within the Department of Transportation and is a Technical Implementation Unit (UPT) responsible to the head of the BMG Meteorology and Geophysics Agency which is a government agency whose task is one of which is to monitor earthquake and potential natural events the tsunami. The geophysical station Mata Ie is located at Latitude 05º 29 ’16.6" LU with Longitude 95º 17 "44.5" East.
|Figure 2. Banda Aceh BMKG Office|
1. Earthquake Source
|Figure 3. Tectonic Plate Globe|
2. Earthquake Parameters
To be able to determine the epicenter of an earthquake, there are several parameters used, namely:
- Origin Time:
Origin Time is the time an earthquake occurs at its source in the earth.
- Epicenter [Latitude and Longitude]
A point or line on the surface of the earth that is perpendicular to the hypocenter.
- Hypocenter [Depth (h)]
The source or place of tectonic, volcanic or ruins causing earthquakes.
- Magnitude [Strength]
Magnitude is an earthquake parameter that is measured based on what happened in a certain area, due to earthquake shocks.
- The earthquake was very large with a magnitude greater than 8 SR.
- Large magnitude earthquake between 7 to 8 SR.
- The earthquake damaged the magnitude between 5 and 6 SR.
- The earthquake was magnitude between 4 to 5 SR.
- Small earthquake with a magnitude of 3 to 4 SR.
- Micro magnitude earthquake between 1 to 3 SR.
- An ultra micro earthquake with a magnitude smaller than 1 SR.
The level of damage that is felt at the location. This scale called MMI (Modified Mercalli Intensity) was introduced by Giuseppe Mercalli in 1902.
3. Seismic Waves
4. Earthquake Strength Measurement
5. Earthquake Classification
Tekntonik earthquake is an earthquake that occurs from the movement of plates or the earth's crust.
b. Volcanic Earthquake
Volcanic earthquake is an earthquake caused by the movement or activity of magma in a volcano.
c. Earthquake Collapse
The earthquake or the earthquake is an earthquake that occurs because of the collapse of the soil or rocks
d. Falling Earthquake
A fall earthquake is an earthquake that occurs as a result of a meteor or rock falling to earth. This falling meteor will cause earth vibrations if the meteor mass is large enough.
f. Artificial Earthquake
An artificial earthquake is an earthquake that occurs due to human activities such as underground or sea nuclear detonation experiments which can cause earth vibrations
|Figure 5. Seismograph (Wikipedia)|
|Figure 6. Seismometer (Kinemetrics)|
|Figure 7. Seismogram (media.npr.org)|
|Figure 8. Seismograf (china.org.cn)|
7. Seismogram Analysis
a. Determination of primary waves
|Figure 9. P Waves|
b. Secondary wave determination
|Figure 10. S Waves|
c. Determine the maximum amplitude
|Figure 11. Maximum Amplitude|
d. Determination of wavelength (duration)
Figure 12. Earthquake Duration
e. Wave magnitude (earthquake strength)
Principles of Analog earthquake seismograph machine
|Figure 13 Analog Seismograph Block Diagram|
1. Seismometer Ranger SS-1
|Figure 14 Seismometer Ranger SS-1|
Seismometer SS-1 Ranger works on the basis of a "moving coil" to produce electricity based on electromagnetic fields. The construction of the Ranger SS-1 can be seen in figure 15. Inside the seismometer there are Spring Hanger Rods, Suspension Spring, Flexure, Output Coil, Mass (moving magnet), Period Extending Magnet, and Calibration Coil ... Spring Hanger Rod and Suspension Spring are useful for control the mass when used in a vertical or horizontal plane. Flexure is useful as an adhesive field for the masses. Coil output is useful as a source of voltage in case of vibrations in the SS ranger 1.
At the output coil there is a Rg resistance coil generator, which is the resistance of the generator coil (coil signal) with Ohms units. The value of this resistance is 5000 Ohms. Mass is a permanent magnet that can move.
The Exteding Magnet Period is useful for expanding the magnetic field to produce a timing. Calibration Coil is used for the calibration process. Calibration functions as a normal determination of the tool's work to show the correct value when measuring. This calibration coil has a resistance of 100Ohm.
Ranger SS-1 is a "spring-mass" instrument with electromagnetic transduction. Permanent magnets are made as seismic "mass" (figure 16) and the output coil as a transducer is attached to a frame or seismometer body (figure 17). The mass is supported by two circular flex, located at the top and bottom which functions as a buffer for the mass (figure 18). A calibration coil is shown in figure 19.
|Figure 15. Ranger SS-1 Construction|
|Figure 16. Mass|
|Figure 17. Transduser coil|
|Figure 18. Flex|
|Figure 19. Calibration Coils|
|Figure 20. Amplifier (red)|
|Figure 21. MS3106E-14S-5S connector (globelink & PEI genesis)|
|Figure 22. Configuring the Connector PIN|
|Figure 23. Analog Recorder|
|Figure 24. Timing in 1 minute / 60 seconds|
Figure 25. Timing in 15 minutes / 900 seconds
|Figure 26. Timing in 24 hours|
|Figure 27. Stepper motor on the recorder|
|Figure 28. Two stepper motors used|
|Figure 29. View of the recording pen|
Figure 30. Back view of a recording pen
|Figure 31. Front view of the selector|
|Figure 32. Back rear of the selector|
|Figure 33. Rear view of Recorder|
|Figure 34. Power Supply|
3. Seismogram analysis
|Figure 35. Recorded earthquake waves|
3.1 Determination of P Waves
|Figure 36. Earthquake position at 09:15|
Figure 37. Analysis of the P wave
3.2 Determining the S Wave
Figure 38. S-wave analysis
3.3 Determination of Amplitude
|Figure 39. Amplitude Analysis|
3.4 Determine the Duration
|Figure 40. Duration Analysis|
3.5 Determination of Impulses
|Figure 41. Impulse analysis|
3.6 Use of OpenOffice Software
|Figure 42. Software Display|
Look at the software in Figure 42, the third column is S-P which is the result of reducing the value of the P wave to the S wave. The results are obtained as follows:
This value is entered with the letter CNE, because when we analyze impulses, we get the value Up (written in C), North, and South. The data that has been obtained, is entered into the software as shown in Figure 43 below:
|Figure 43. Data entered|
3.7 Seismometer Location
|Figure 44. Seismometer location|
|Figure 45. Laying of a Seismometer|