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@copyright by Jurnal Migasian, ISSN-p-2580-5258;ISSN-e-2615-6695
Jurnal Migasian
ISSN-p-2580-5258;ISSN-e-2615-6695
Vol.3 No.2: 21-24, Desember 2019
21
Design of Real-Time Seismic Amplitude Measurement (RSAM) System Using
Geophone as the Detection of Seismic Vibration
Umi Salamah1, Apik Rusdiarna I.P2, Qonitatul Hidayah3 Aji Nur Rizki4
1,2,3,4 Program Studi Fisika, Fakultas Sains dan Teknologi Terapan, Universitas Ahmad Dahlan Yogyakarta
Jl. Prof. Dr. Soepomo, Janturan, Warungboto, Yogyakarta
*)E-mail: umi.salamah@fisika.uad.ac.id
Abstrak
Indonesia merupakan salah satu negara dengan gunungapi terbanyak di dunia. Indonesia memiliki 129 gunungapi aktif, 70
buah diantaranya berancaman dan 500 buah tidak aktif. Sejak tahun 1800, paling tidak telah tercatat 600 kali letusan oleh 70
gunungapi di Indonesia. Karena itu, Indonesia dapat dikatakan sebagai negara yang rawan bencana gunung berapi.
Pengamatan, pemantauan, pencatatan, penyebaran informasi dan peringatan tanda bahaya terhadap aktivitas gunungapi
menjadi salah satu fokus dalam penanggulangan bencana gunungapi. Untuk mendukung hal tersebut diperlukan instrumentasi
deteksi aktivitas vulkanik gunungapi. Salah satu instrumentasi yang digunakan untuk memantau aktivitas gunung berapi
Gunung Merapi adalah Real-time Seismic Amplitude Measurement (RSAM). RSAM adalah sistem pengukuran kontinu dari
amplitudo seismik rata-rata absolut dari jumlah stasiun seismik. RSAM menempati peran strategis dalam memantau aktivitas
seismik gunung berapi terutama pada saat krisis sebelum letusan. Dalam penelitian ini, perancangan sistem RSAM
menggunakan sensor geophone untuk mendeteksi getaran seismik. Frekuensi tes yang diberikan dalam penelitian ini termasuk
10 Hz, 30 Hz, dan 50 Hz. Sistem yang telah dirancang bangun dapat mendeteksi frekuensi dengan baik sebagaimana
dibuktikan bahwa semakin besar frekuensi uji maka semakin banyak output grafik yang dihasilkan. Selain itu, magnitudo
yang dihasilkan juga semakin besar. Pada frekuensi 10 Hz, magnitudo yang dihasilkan adalah 0,997, pada 30 Hz magnitudo
yang dihasilkan 1,559 sedangkan pada 50 Hz magnitudo yang dihasilkan adalah 1,962. Sistem RSAM yang dirancang bangun
menghasilkan amplitudo yang memiliki hubungan linier dengan besarnya getaran sumber disediakan.
Kata Kunci: Geophone, RSAM, Getaran Seismik.
Abstract
Indonesia is one of the most volcanic countries in the world. Indonesia has 129 active volcanoes, 70 of which are threatened
and 500 are inactive. Since 1800, at least 600 recorded eruptions by 70 volcanoes in Indonesia. Therefore, Indonesia can be
regarded as a country prone to volcano disaster. Observation, monitoring, recording, dissemination of information and warning
signs of volcanic activity to be one focus in volcano disaster mitigation. One of the instrumentations used to monitor the
volcanic activity of Mount Merapi is Real-time Seismic Amplitude Measurement (RSAM). RSAM is a continuous
measurement system of the absolute average seismic amplitude of the number of seismic stations. RSAM occupies a strategic
role in monitoring the seismic activity of volcano especially in times of crisis before the eruption. In this research, the RSAM
system design using a geophone sensor to detect the seismic vibration. The frequency tests given in this study included 10 Hz,
30 Hz, and 50 Hz. The system that has been designed to build can detect frequencies well as evidenced by the greater the
frequency of the test given the more the graph output of the output is produced. In addition, the magnitude produced is also
getting bigger. At a frequency of 10 Hz, the resulting magnitude is 0.997, at 30 Hz the resulting magnitude is 1.559 while at
50 Hz the magnitude generated is 1.962 The RSAM system designed to build produces an amplitude that has a linear
relationship to the magnitude of the vibration source provided.
Keywords: Geophone, RSAM, Seismic Vibration.
1. Introduction
Indonesia has 129 active volcanoes, 70 of which are
threatened and 500 inactive. Therefore, Indonesia is one of
the country prone to volcanic disasters. Generally,
volcanic activity is started by the extrusion of magma on
the lava dome which is accompanied by the partial
collapse of the lava dome which causes rock avalanches
and pyroclastic avalanches, until a big eruption [1].
@copyright by Jurnal Migasian, ISSN-p-2580-5258;ISSN-e-2615-6695
Jurnal Migasian – AKAMIGAS Balongan Vol.3 No.2;21-24, Desember 2019
Design of Real-Time Seismic Amplitude Measurement (RSAM) System Using Geophone as the
Detection of Seismic Vibration
22
Detection of volcanic activity starting from observation,
monitoring, recording, dissemination of information and
warning signs of volcanic activity is very important for the
prevention of volcanic disasters
One of the instrumentations used to monitor
volcanic activity is Real-time Seismic Amplitude
Measurement (RSAM). RSAM is a system that provides a
continuous measurement of the absolute average seismic
amplitude of the number of seismic stations [2]. RSAM
occupies a strategic role in monitoring the seismic activity
of volcano especially in times of crisis before the eruption.
In 2010, the eruption of Mount Merapi was also used as an
instrumentation which was used to analyze the seismic
activity of Mount Merapi observed by applying the
Material Failure Forecast (FFM) method and getting better
data on Mount Merapi activity [3]. The RSAM system can
be connected with several types of sensors for the
detection of seismic volcano vibrations. Geophone is one
of the potential sensors to use. Geophone is a sensor that
is able to detect seismic vibrations in low frequency and
high frequency. In this research, we will design RSAM by
utilizing developing and popular micro system that is
currently using Arduino and geophone as sensors.
2. Fundamental Theory
2.1 Type of Volcanic Eruption Material
The initial symptoms of volcanic eruption are
monitored with the seismic of the volcano. Symptoms of
increased activity starts from the emergence of
chronological series of volcanic earthquakes, lava and hot
clouds. Seismic development is interpreted as a reflection
of the migration of magma from depth to surface until the
eruption occurs. The release of magma to the surface of
the earth in different forms. Among Volcanic Gas, lava,
lava flow pyroclastic and pyroclastic fall (rain ash). Lava
is a high-temperature magma liquid that flows to the
surface through volcanoes. Lava is able to flow away from
its source. While lava is a stream of mud and rock so that
the ability to flow is not too far [4].
2.2 Real-time Seismic Amplitude Measurement (RSAM)
RSAM is the output of the average amplitude
recorded at a certain time using Earthworm software. The
principle of RSAM is that the signal that enters the
digitizer is rectified, meaning that the negative signal is
reversed to positive, after that it is sampled and then on
average every 10 minutes. Thus, the RSAM actually
measures the energy of all earthquakes recorded at seismic
stations without distinguishing the type of earthquake [5].
The magnitude of the vibration of earthquakes shown in
Equation 1 below:
𝑀 = 𝑀𝐴 =𝑙𝑜𝑔𝐴 − 𝐿𝑜𝑔𝐴𝑜 (1)
Where M is Magnitude, A is the amplitude on a
seismogram based on ‘Wood Anderson’(gain 2800×)
seismograph, Ao is the minimum amplitude for
seismogram ‘Wood Anderson, the magnitude depends on
the distance of the epicenter [6].
3. Methodology
The RSAM design is started by selecting electronic
design components, digital communication and digital
signal processing. The RSAM module has been designed
that is connected with a geophone sensor and tested on a
laboratory scale before being tested on a field scale. The
computerized RSAM system diagram block is shown in
Figure 1.
Figure 1. Block computerized RSAM system diagram
Initial RSAM testing is carried out on a laboratory
scale. Laboratory scale testing is carried out at the RSAM
signal output using the PC Multimeter link, to determine
the geophone response that is provided to the artificial
vibration. The vibration response testing system uses an
Audio Frequency Generator (AFG) that is connected to the
vibration source, which is a speaker that is modified with
an amplifier. Frequency variations are used ranging from
10 Hz to 50 Hz with an increase of 5 Hz. In the next step,
still at the stage of laboratory scale testing, interface
testing is done for computerization. The interface display
is shown in Figure 2.
PC
Interfacing
Data Processing
RSAM
ADC
Amplifier
@copyright by Jurnal Migasian, ISSN-p-2580-5258;ISSN-e-2615-6695
Jurnal Migasian – AKAMIGAS Balongan Vol.3 No.2;21-24, Desember 2019
Design of Real-Time Seismic Amplitude Measurement (RSAM) System Using Geophone as the
Detection of Seismic Vibration
23
23
Figure 2. RSAM system interface
Data analysis is done by calculating the magnitude,
namely the scale of strength measured by the vibrations
that happen. In the formulation of quantities, a basic
Richter scale formulation is used as shown in Equation 1.
4. Results and Discussion
Photographs of the RSAM system electronic circuit design
are shown in Figure 3 below.
Figure 3. Electronic module of the RSAM system
The hardware system consists of RSAM electronic
modules arranged in a series of Analog to Digital
Converter (ADC) using Arduino. The RSAM series is
associated with geophone as a seismic sensor.
The computerized RSAM system is tested early to
detect whether the system can obtain data correctly. The
results of the initial testing in this research are shown in
Figure 4.
Figure 4. Graph of Initial RSAM System Test Results
The graph shown in Image 4 is a RSAM system
response graph with triggered vibrations. From the graph,
the response of the RSAM system is given vibration that
is quite good, it is seen in the data acquisition that is carried
out by the 100 ms system so that the response is fast.
Furthermore, the RSAM system is designed that is tested
with frequency variations, at low, medium and high
frequencies. The frequency variations used are 10 Hz, 30
Hz and 50 Hz. Figure 5 below shows a frequency response
graph at each given frequency.
(a)
(b)
(c)
Figure 5. Test Results for Response Frequency (a) 10 Hz,
(b) 30 Hz and (c) 50 Hz
Geophone
Arduino
RSAM
module
@copyright by Jurnal Migasian, ISSN-p-2580-5258;ISSN-e-2615-6695
Jurnal Migasian – AKAMIGAS Balongan Vol.3 No.2;21-24, Desember 2019
Design of Real-Time Seismic Amplitude Measurement (RSAM) System Using Geophone as the
Detection of Seismic Vibration
24
From the tests conducted, it can be seen that the
frequency response has a relative track according to the
input frequency is given it, that is the greater the frequency
of the test that is given the more wave envelopes produced.
The magnitude of the resulting graph is calculated
using Equation 2.1. while the magnitude obtained is shown
in Table 1
Table 1. The magnitude of vibration with respect to the
variation in frequency given
Input frequency (Hz)
The magnitude of
the Richter scale
10
0.997
30
1.559
50
1.962
From the table above it can be seen that the greater
the source of vibration given the greater the amount
produced. This proves that the RSAM system designed to
build with geophone is able to detect vibrations well
5. Conclusion
Geophone as a vibration sensor on the RSAM system
can detect vibrations well. At the frequency of testing the
resulting wave envelope increases and the size also
increases. At a frequency of 10 Hz, the resulting
magnitude is 0.997, at 30 Hz the resulting magnitude is
1.559 while at 50 Hz the magnitude generated is 1.962
Suggestion
In future studies it is recommended to increase the
test frequency with more than one sensor point.
Acknowledgment
KEMENRISTEK-DIKTI has funded this research with
contract number PDP-043 / SKPP / 2018
References
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