An update to seismic hazard levels and PSHA for Lombok and surrounding islands after earthquakes in 2018

  • Didi S Agustawijaya University of Mataram, Mataram
  • Rian M Taruna The Indonesian Agency for Meteorology, Climate and Geophysics (BMKG), Mataram
  • Ausa R Agustawijaya ITS, Surabaya


A series of earthquakes occurred at the northern part of Lombok Island during July–September 2018 with the highest Mw7.0 5th August 2018 that caused the death of hundreds of people and ruined thousands of buildings. The earthquakes were triggered on the Flores Thrust located at the back arc zone and at only 50 km distance from the island, leading to multiple seismic hazards to Lombok and surrounding islands. The thrust could possibly be the dominant current seismic sources; however, the megathrust sources also contributed to the hazards due to the subduction between the Indo-Australia and Eurasia tectonic plates in the Nusa Tenggara region. An updated probabilistic seismic hazard analysis was, therefore, conducted on recent seismicity, detailed tectonic background, and suitable ground motion prediction equations, to determine higher seismic parameter values than the 2017 models. This means that Lombok and surrounding islands exposed to higher seismic hazards than those predicted before the earthquake events in 2018.

Author Biographies

Didi S Agustawijaya, University of Mataram, Mataram

Professor, Department of Civil Engineering

Rian M Taruna, The Indonesian Agency for Meteorology, Climate and Geophysics (BMKG), Mataram


Ausa R Agustawijaya, ITS, Surabaya

Student, Department of Geomatics Engineering


Indonesian Agency for Meteorology, Climate and Geophysics (BMKG) (2019). new/

Indonesian Agency for Meteorology, Climate and Geophysics (BMKG) (2018). Press Release No: UM.505/3/D3/VIII/2018 (in Indonesian).

Pramono S (2018). “Perencanaan Rekonstruksi Wilayah Lombok Berbasis Mitigasi Gempabumi”. Indonesian Agency for Meteorology, Climate and Geophysics (BMKG) (in Indonesian).

Hamilton W (1974). “Earthquake Map of Indonesian Region”. USGS, Folio of the Indonesia Region, Map 1-875-C, Scale 1:5000000.

Hamilton W (1979). “Tectonics of the Indonesian Region”. US Geological Survey Professional Paper 1078, 345 pp.

Bock Y, Prawirodirdjo L, Genrich JF, Stevens CW, McCaffrey R, Subarya C, Puntodewo SSO and Calais E (2003). “Crustal Motion in Indonesia from Global Positioning System Measurements”. Journal of Geophysical Research, 108: 2367.

Koulali A, Susilo S, McClusky S, Meilano I, Cummins P, Tregoning P, Lister G, Efendi J, and Syafi’i MA (2016). “Crustal Strain Partitioning and the Associated Earthquake Hazard in the Eastern Sunda-Banda Arc”. Geophysical Research Letters, 43: 1943–1949.

Pranantyo IR and Cummins PR (2019). “Multi-Data-Type Source Estimation for the 1992 Flores Earthquake and Tsunami”. Pure and Applied Geophysics.

Agustawijaya DS, Karyadi K, Krisnayanti BD and Sutanto S (2017). “Rare Earth Element Contents of the Lusi Mud: An Attempt to Identify the Environmental Origin of the Hot Mudflow in East Java – Indonesia”. DeGruyter Open Geoscience, 9: 689–706.

Katili JA (1989). “Evolution of the Southeast Asian Arc Complex”. Geologi Indonesia, 12(1): 113-143.

Verstappen MT (2010). “Indonesian Landforms and Plate Tectonics”. Indonesian Journal on Geoscience, 5(3): 197-207.

Nugraha AD, Kusnandar R, Puspito NT, Sakti AP and Yudistira T (2014). “Preliminary Results of Local Earthquake Tomography around Bali, Lombok, and Sumbawa Regions”. AIP Conference Proceedings, 1658: 030019-1-030019-4.

Setyono U, Gunawan I, Priyobudi et al. (2019). “Katalog Gempabumi Signifikan dan Merusak 1821-2018”. Pusat Gempabumi dan Tsunami, Badan Mateorologi, Klimatogi dan Geofisika, Jakarta (in Indonesian).

Gusman AR, Tanioka Y, Matsumoto H and Iwasaki SI (2009). “Analysis of the Tsunami generated by the Great 1977 Sumba Earthquake that Occurred in Indonesia”. Bulletin of the Seismological Society of America, 99(4): 2169–2179.

Irsyam M, Widiyantoro S, Natawidjaja D, Meilano I, Rudyanto A, Hidayati S, Triyoso W, Hanifa N, Djarwadi D, Faizal L and Sunarjito S (2017). “Peta Sumber dan Bahaya Gempa Indonesia Tahun 2017”. Bandung. Pusat Gempa Nasioal (PUSGEN), Kementerian Pekerjaan Umum dan Perumahan Rakyat, 376 pp. (in Indonesian).

Hamilton W (1989). “Convergent-Plate Tectonics Viewed from the Indonesian Region”. Geology of Indonesia, 12(1): 35-88.

Badan Standardisasi Nasional (BSNI) (2019). “SNI 1726:2019 Tata Cara Perencanaan Ketahanan Gempa Untuk Struktur Bangunan Gedung dan Non Gedung”. 238 pp. (in Indonesian).

United State Geological Survey (USGS) (2018).

International Seismological Centre (ISC) (2019).

Papazachos BC, Scordilis EM, Panagiotopoulos DG, Papazachos CB and Karakaisis GF (2004). “Global Relations between Seismic Fault Parameters and Moment Magnitude of Earthquakes”. Bulletin of the Geological Society of Greece, XXXVI: 1482–1489.

Asrurifak M, Irsyam M, Budiono B, Triyoso W and Hendriyawan (2010). “Development of Spectral Hazard Map for Indonesia with a Return Period of 2500 Years Using Probabilistic Method”. Civil Engineering Dimension, 12(1): 52-62.

Gutenberg B and Richter C (1949). “Seismicity of the Earth and Associated Phenomena”. Princeton University Press, New Jersey, 273 pp.

Marzocchi W and Sandri L (2003). “Review and New Insights on the Estimation of the B-Value and Its Uncertainty”. Analysis of Geophysics, 46(6): 1271-1282.

Utsu T (1965). “A Method for Determining the Value of b in a Formula Log N = a – bM Showing the Magnitude Frequency for Earthquakes”. Geophysical Bulletin of the Hokkaido University, 13: 99–103.

Douglas J (2017). “Ground Motion Prediction Equations 1964-2017”. Report, Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, United Kingdom, 595 pp.

Joyner WB and Boore DM (1988). “Measurement, Characterization, and Prediction of Strong Ground Motion”. Proceedings of Earthquake Engineering & Soil Dynamics, II: 43-102. Geotechnical Division, ASCE.

Boore DM and Atkinson GM (2008). “Ground-Motion Prediction Equations for the Average Horizontal Component of PGA, PGV, and 5%-damped PSA at Spectral Periods between 0.01 s and 10.0 s”. Earthquake Spectra, 24(1): 99-138.

Agustawijaya DS, Sulistiyono H and Elhuda I (2018). “Determination of the Seismicity and Peak Ground Acceleration for Lombok Island: An Evaluation on Tectonic Setting”. MATEC Web of Conference, 195: 03018.

Ashadi AL, Harmoko U, Yuliyanto G and Kaka SI (2015). “Probabilistic Seismic Hazard Analysis for Central Java Province, Indonesia”. Bulletin of the Seismological Society of America, 105(3): 1711–1720.

Gardner JK and Knopoff L (1974). “Is the Sequence of Earthquakes in Southern California, with Aftershocks Removed, Poissonian?”. Bulletin of the Seismological Society of America, 64(5): 1363-1367.

Wiemer S (2001). “A Software Package to Analyze Seismicity: ZMAP”. Seismological Research Letters, 72(2): 373–382.

Jones ES, Hayes GP, Bernardino M, Dannemann FK, Furlong KP, Benz HM and Villaseñor A (2014). “Seismicity of the Earth 1900–2012 Java and Vicinity”. USGS Open-File Report 2010–1083-N, 1 sheet, Scale 1:5000000.

Kompas. (Accessed 9 August 2018)

Sunardi B, Istikomah M and Sulastri (2017). “Analisis Seismotektonik dan Periode Ulang Gempabumi Wilayah Nusa Tenggara Barat, Tahun 1973-2015”. Jurnal Riset Geofisika Indonesia, 1(1): 23-28 (in Indonesian).

Griffin J, Nguyen N, Cummins P and Cipta A (2019). “Historical Earthquakes of the Eastern Sunda Arc: Source Mechanisms and Intensity-Based Testing of Indonesia’s National Seismic Hazard Assessment”. Bulletin of the Seismological Society of America, 109(1): 43-65.

Pusat Studi Gempa Nasional (PUSGEN) (2018). “Kajian Rangkaian Gempa Lombok Provinsi Nusa Tenggara Barat”. Kementerian Pekerjaan Umum dan Perumahan Rakyat, Jakarta, ISBN 978-602-5489-13-6, 196 pp.

Mogi K (1962). “Magnitude-Frequency Relationship for Elastic Shocks Accompanying Fractures of Various Materials and Some Related Problems in Earthquakes”. Bulletin of the Earthquake Research Institute, University of Tokyo, 40: 831-883.

Scholz C (1968). “Microfractures, Aftershocks and Seismicity”. Bulletin of the Seismological Society of America, 58(3): 1117-1130.

McCaffrey R and Nabelek J (1987). “Earthquakes, Gravity, and the Origin of the Bali Basin: An Example of a Nascent Continental Fold-and-Thrust Belt”. Journal of Geophysical Research, 92(B1): 441-460.

Tsukakoshi Y and Shimazaki K (2008). “Decreased B-value prior to the M 6.2 Northern Miyagi, Japan, Earthquake of 26 July 2003”. Earth, Planets and Space, 60: 915–924.

Shi Y and Bolt B (1982). “The Standard Error of the Magnitude-Frequency B Value”. Bulletin of the Seismological Society of America, 72(5): 1677-1687.

Gulia L and Wiemer S (2019). “Real-Time Discrimination of Earthquake Foreshocks and Aftershocks”. Nature, 574(7777): 193–199.

Okal A and Romanowicz BA (1994). “On the Variation of b-Values with Earthquake Size”. Physics of the Earth and Planetary Interiors, 87: 55-76.

Hadley D, Helmberger D and Orcutt JA (1982). “Peak Acceleration Scaling Studies”. Bulletin of the Seismological Society of America, 72(3): 959-979.

Youngs RR, Chiou SJ, Silva WJ and Humphrey JR (1997). “Strong Ground Motion Attenuation Relationships for Subduction Zone Earthquakes”. Seismological Research Letters, 68: 58–73.

Boore D (2015). “Ground Motion Prediction Equations: Past, Present, and Future”. The 2014 William B. Joyner Lecture, the SMIP15 Meeting, Davis, California, 22 October 2015, 93 pp.

Kencanawati NN, Agustawijaya DS and Taruna RM (2020). “An Investigation of Building Seismic Design Parameters in Mataram City Using Lombok Earthquake 2018 Ground Motion”. Journal of Engineering and Technological Sciences, 52(5): 651-664 .

Ardian Y, Santoso E, Kaluku A, Dawwam F, Sakti AP, Pramono S and Permana D (2018). “Ulasan Guncangan Tanah Akibat Gempa Lombok Timur 05 Agustus 2018”. BMKG, 21 pp (in Indonesian).

Douglas J and Boore DM (2018). “Peak Ground Accelerations from Large (M7.2) Shallow Crustal Earthquakes: A Comparison with Predictions from Eight Recent Ground-Motion Models”. Bulletin of Earthquake Engineering, 16: 1–21.

Indonesian Ministry for Public Work and Homes (PUSKIM) (2011). “Desain Spectra Indonesia”. Pusat Penelitian dan Pengembangan, Kementerian Pekerjaan Umum (in Indonesian). (Accessed 27 July 2019)

Agustawijaya DS, Sulistyowati T, Layli BA and Agustawijaya AR (2019). “The Ground Deformation of the Luk Barat Bridge after Lombok Earthquakes 2018”. IOP Conference Series: Earth and Environmental Science, 389: 012051.

National Research Council (NRC) (1988). “Probabilistic Seismic Hazard Analysis”. The National Academies Press, Washington DC, 111 pp.

Grunthal G, Stromeyer D, Bosse C, Cotton F and Bindi D (2018). “The Probabilistic Seismic Hazard Assessment of Germany—Version 2016, Considering The Range of Epistemic Uncertainties and Aleatory Variability”. Bulletin of Earthquake Engineering, 16: 4339–4395.

Baker WJ (2008). “An Introduction to Probabilistic Seismic Hazard Analysis, Version 1.3”, 72 pp.

Atkinson GM and Boore DM (2003). “Empirical Ground Motion Relations for Subduction Zone Earthquakes and Their Application to Cascadia and Other Regions”. Bulletin of the Seismological Society of America, 93: 1703–1729.

Zhao JX, Zhang J, Asano A, Ohno Y, Ouchi T, Takahashi T, Ogawa H, Irikura K, Thio H and Somerville P (2006). “Attenuation Relations of Strong Ground Motion in Japan using Site Classification Based on Predominant Period”. Bulletin of the Seismological Society of America, 96: 898–913.

Campbell KW and Bozorgnia Y (2008). “NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10 s”. Earthquake Spectra, 24(1): 139–171.

Chiou B and Youngs R (2008). “An NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra”. Earthquake Spectra, 24(1): 173–215.

Taruna RM (2019). “Intensitas Kegempaan Kota Mataram Berdasarkan Data Gempabumi Tahun 1922-2018”. Masters Thesis, University of Mataram, 82 pp (in Indonesian).

McGuire RK (2004). ”Seismic Hazard and Risk Analysis”. Earthquake Engineering Research Institute, MNO-10, Oakland, CA, 221 pp.

Gerstenberger MC, Rhoades DA and McVerry GH (2016). “A Hybrid Time-Dependent Probabilistic Seismic Hazard Model for Canterbury, New Zealand”. Seismological Research Letters, 87(6): 1311–1318.

Horspool N, Pranantyo I, Griffin J, Latief H, Natawidjaja DH, Kongko W, Cipta A, Bustaman B, Anugrah SD and Thio HK (2014). “A Probabilistic Tsunami Hazard Assessment for Indonesia”. Natural Hazards and Earth System Science, 14: 3105–3122.

Nguyen N, Griffin J, Cipta A and Cummins PR (2015). “Indonesia’s Historical Earthquakes: Modelled Examples for Improving the National Hazard Map”. Geoscience Australia, Record 2015/23, Canberra.

Griffin J and Davies G (2018). “Earthquake Sources of the Australian Plate Margin: Revised Models for the 2018 National Tsunami and Earthquake Hazard Assessments”. Geoscience Australia, Record 2018/31, Canberra.

Zubaidah T, Korte M, Mandea M and Hamoudi M (2014). “New Insights into Regional Tectonics of the Sunda–Banda Arcs Region from Integrated Magnetic and Gravity Modeling". Journal of Asian Earth Science, 80: 172–184.

Rohadi S (2009). “Studi Seismotektonik sebagai Indikator Potensi Gempabumi di Wilayah Indonesia”. Jurnal Meteorologi dan Geofisika, 10(2): 111–120 (in Indonesian).

Worden CB, Gerstenberger MC, Rhoades DA and Wald D J (2012). “Probabilistic Relationships between Ground Motion Parameters and Modified Mercalli Intensity in California”. Bulletin of the Seismological Society of America, 102(1): 204–221.

Sina DT (2011). “Evaluasi Bahaya Gempa (Seismic Hazard) dengan Menggunakan Metode Point Source dan Penentuan Respons Spektra Desain Kota Kupang”. Jurnal Teknik Sipil, 1(1): 41-51 (in Indonesian).

Kinasih G, Wiriasto W, Kanata B and Zubaidah T (2014). “Lesser Sunda Islands Earthquake Inter-Occurrence Times Distribution Modeling”. International Journal of Technology, 3: 242-250.

Harmsen S (2007). “USGS Software for Probabilistic Seismic Hazard Analysis (PSHA)”. USGS. (Unpublished Manuscript).

How to Cite
Agustawijaya, D. S., Taruna, R. M., & Agustawijaya, A. R. (2020). An update to seismic hazard levels and PSHA for Lombok and surrounding islands after earthquakes in 2018. Bulletin of the New Zealand Society for Earthquake Engineering, 53(4), 215-226.