Analysis of a Peak Ground Acceleration Value and Earthquake Intensity Using Donovan Method in Banten Province
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SPEKTRA: Jurnal Fisika dan Aplikasinya Volume 5, Issue 3, December 2020 Homepage: doi.org/10.21009/SPEKTRA . 01 DOI: doi.org/10.21009/SPEKTRA.053.05 ANALYSIS OF A PEAK GROUND ACCELERATION VALUE AND EARTHQUAKE INTENSITY USING DONOVAN METHOD IN BANTEN PROVINCE Elsi Ariani* Department of Physics, UIN Sultan Maulana Hasanuddin Banten, Banten, Indonesia *Corresponding Author Email: [email protected] Received: 27 July 2020 ABSTRACT Revised: 15 September 2020 Accepted: 22 October 2020 Analysis of a peak ground acceleration value and earthquake intensity Online: 1 December 2020 in Banten Province has been carried out using historical earthquake Published: 31 December 2020 data from 2008 to 2018. This research aims to describe a prone area SPEKTRA: Jurnal Fisika dan of the earthquake. The specification of data was a magnitude > 5 SR Aplikasinya and the depth 0-70 km. The Donovan method was used to analyze p-ISSN: 2541-3384 peak ground acceleration value and the earthquake’s intensity. e-ISSN: 2541-3392 According to the data obtained, 31 earthquake points with a maximum earthquake strength occurred on October 16, 2019, with a depth of 10 km and a magnitude of 6.48 SR. This earthquake was located in Ujung Kulon with coordinates -6.81 LS and 105.113 BT. Based on data analysis result was obtained a peak ground acceleration value and the intensity of earthquake maximum in The Pandeglang Regency with a peak ground acceleration value was 211.56 cm/s2, and intensity of scale VIII and a large risk level of three. While a peak ground acceleration minimum is located in the South Tangerang City was 62.82 cm/s2 with a scale of intensity VII and a moderate risk level. Keywords: earthquake, peak ground acceleration, intensity, Donovan method, Banten province | 213 SPEKTRA: Jurnal Fisika dan Aplikasinya Volume 5 Issue 3, December 2020 INTRODUCTION The Indonesian country is an archipelago state on the located encounter of three of the plate are Eurasian plate, Indo Australian plate, and Pacific plate [1]. This condition often induces to happen the earthquake in tectonic and volcanic. Another earthquake trigger is the formation of a subduction zone. A subduction zone is a state where one tectonic plate falls under another tectonic plate. This subduction route extends along the west coast of Sumatra Island, along the south of Java Island, south of Bali, Lombok, Flores, Maluku, and Papua. Java Island is located between Eurasia and Indo-Australian plates. The movement of this plate is about 6.5 cm/ year around Java and Bali. In the south of the island of Java, the subduction path of the Indo Australian plate is relative to the north against the Eurasian plate, while the Pacific plate moves westward relative to the Eurasian plate and the Indo Australian plate. Earthquakes often occur in an area where tectonic plates meet, which results in a higher earthquake stage in the region. Earthquakes may trigger damage to the construction of buildings. Damage to the construction of buildings is not only caused by the quality of the building being built but also the condition of the land on which the building stands, which can be seen from the level of reinforcement, land retaliation against shocks, and maximum ground acceleration. Based on the information from the Directorate of volcanology and geological disaster mitigation, the ministry of energy and mineral resources recorded 28 earthquake-prone areas in Indonesia. One of them is the Banten Province [2]. About 45% of the Banten Province is prone to the earthquake. In the West and South are the prone area, the tectonic earthquake cause this area is passed the Indo Australian plate and Eurasian plate [3]. Furthermore, in the Banten Province are the Sunda microplates. There are the zoning zone of microplates and the seismogenic structure that can trigger and cause the earthquake around the Sunda strait [4]. Based on the observations made, the researcher of the earthquake that occurred in Banten Province from 2008 until 2018 with magnitude is > 5 SR. This amount is taken because it has caused damage to structures such as cracks in the wall. The depth is used 0 km until 70 km where were 31 the earthquake points. The following data is shown in FIGURE 1: FIGURE 1. The distribution of earthquake points in Banten Province in 2008-2018 | 214 SPEKTRA: Jurnal Fisika dan Aplikasinya Volume 5 Issue 3, December 2020 TABLE 1 shows the time of the location of the depth and magnitude of the earthquake at each point: TABLE 1. Data of Earthquake in Banten Province from 2008 until 2018 [5]. No Time Location Depth (Km) Magnitude (SR) 1 2008-11-15 13:00:46 A1 10 5.22 2 2009-03-27 20:53:28 A2 27.7 5.15 3 2009-10-24 03:09:53 A3 14.7 5.06 4 2009-10-16 09:52:50 A4 10 6.48 5 2010-02-20 04:57:33 A5 10 5.03 6 2010-08-11 19:10:23 A6 50.1 5.47 7 2011-01-12 12:44:45 A7 13.1 5.33 8 2011-03-20 01:20:13 A8 10 5.32 9 2011-04-05 04:34:43 A9 49.8 5.1 10 2011-07-17 10:59:09 A10 57.8 5.18 11 2011-08-21 16:54:19 A11 25.8 5.08 12 2012-04-14 19:31:46 A12 20.8 5.36 13 2012-04-14 19:26:41 A13 69.8 5.75 14 2012-06-04 11:18:14 A14 69.6 5.71 15 2013-02-02 01:19:32 A15 10 5.33 16 2013-04-08 18:53:44 A16 48.4 5.17 17 2014-01-09 16:16:48 A17 10 5.36 18 2014-01-05 11:32:10 A18 40.6 5 19 2014-07-09 00:01:32 A19 39.2 5.08 20 2015-11-04 06:14:35 A20 40.1 5.04 21 2016-08-12 07:17:15 A21 50.3 5.07 22 2017-02-08 08:34:17 A22 69.7 5.04 23 2017-07-08 22:48:37 A23 57.3 5.07 24 2017-12-16 00:22:30 A24 37.1 5.44 25 2018-01-26 10:12:50 A25 29.8 5.02 26 2018-01-26 04:48:25 A26 30 5.15 27 2018-01-23 06:34:54 A27 46.2 6.09 28 2018-02-16 13:28:10 A28 48.9 5.03 29 2018-02-16 05:13:02 A29 10 5.09 30 2018-03-19 11:36:27 A30 40.4 5.18 31 2018-10-29 21:11:19 A31 64.7 5.28 Based on TABLE 1, we can see that the maximum earthquake occurred on October 16, 2009, with a depth of 10 km and a magnitude of 6.48 SR. The earthquake is located around Sunda strait is in the west end of Ujung Kulon with coordinates -6.81 LS and 105.113 BT. In 2018, in the Lebak District occurred an earthquake with a magnitude 6.1 SR. Consequently, there is 1 died, and the 1231 house damaged consists of 1125 light damaged and 106 heavily damaged. The damaged located 16 sub-district on the south coast Banten. Some of the school buildings were damaged too. | 215 SPEKTRA: Jurnal Fisika dan Aplikasinya Volume 5 Issue 3, December 2020 In an effort to minimize damage caused by earthquakes, it is necessary to mitigate earthquake disasters by conducting further studies of the spatial area of Banten. One step that can be done is to analyze the value of the peak ground acceleration and intensity of the earthquake that occurred in the Banten Province. The maximum land shed approach needs to be taken in order to determine the form of building coaching and improve the spatial structure of the areas exposed to earthquakes. The estimation of the maximum land squatter value can be determined in 2 (two) ways, namely by using an acelograph and by using an empirical approach. Some of the methods used through an empirical approach include Gutteberg Richter, Donovan, Esteva, Fukushima Tanaka, Murphy O’brein, Mc Guirre and Kanai. When an earthquake occurs, a ground acceleration value will be generated somewhere [6]. The value of ground acceleration needed in calculating the design of the building is the peak ground acceleration value. The motion of a peak ground acceleration (PGA) is the biggest value from the ground acceleration in a place caused the earthquake [7]. Although earthquakes with large forces do not occur often, they are still dangerous to human life. This acceleration value indicates the level of risk of damage that will arise to the building. This is needed in adjusting the strength of buildings to be built in the area. Therefore, it is necessary to analyze the value of the peak ground acceleration and intensity of the earthquake that occurred in Banten Province. METHOD The Donovan method is one of the methods used to calculate the value of a peak ground acceleration in an area. This method has been widely used by previous investigators in determining the maximum land fraction value in various regions of Indonesia. In 2018 Dwi Romadiana, Syafriani, and Andiyansyah conducted an investigation in analyzing the maximum ground acceleration value in the West Sumatra region using the Donovan method [8]. Apart from that, Cloudya Gabriella Kapojos, Gerald Tamuntuan, and Guntur Pasau have also used the Donovan method in their investigations to analyze the maximum land shed in the North Peninsula area of Sulawesi Island.