Indonesia Earthquake

HISTORY, PREVIOUS RESEARCH, RECENT EARTHQUAKE

PUTIKA ASHFAR KHOIRIputika@civil.osaka-u.ac.jp

R E F E R EN C ES :

1. FAUZI, USAMA JUNIANSYAH. FAUZI, ACHMAD. IRSYAM, MASYHUR.2011. PROPOSED LONG PERIOD TRANSITION MAP FOR NEW INDONESIA EARTHQUAKE RESISTANT BUILDING CODE BASED ON INDONESIA SEISMIC HAZARD MAP 2010. PROCEEDING OF ANNUAL INTERNATIONAL CONFERENCE SYIAH KUALA UNIVERSITY. PP. 202-209

2. GUNAWAN, ENDRA. KHOLIL, MUNAWAR. MEILANO, IRWAN. 2016. SPLAY-FAULT RUPTURE DURING THE 2014 MW7.1 MOLUCCA SEA, INDONESIA, EARTHQUAKE DETERMINED FROM GPS MEASUREMENTS. PHYSICS OF THE EARTH AND PLANETARY INTERIORS. 259 PP. 29-33

3. SATAKE, KENJ I . THE 2004 SUMATRA-ANDAMAN EARTHQUAKE AND TSUNAMI IN THE INDIAN OCEAN. GEOLOGICAL SURVEY OF JAPAN.

4. SETIAWAN, BAMBANG. 2013. BANDA ACEH-INDONESIA GROUND RESPONSE ANALYSIS DURING THE 2004 INDIAN OCEAN MEGA EARTHQUAKE.SEVENTH INTERNATIONAL CONFERENCE ON CASE HISTORIES IN GEOTECHNICAL ENGINEERING. P. 404.A

5. VERSTAPPEN, H. TH. 2010. INDONESIAN LANDFORMS AND PLATE TECTONICS. JURNAL GEOLOGI INDONESIA, VOL. 5, PP. 197-207

6. WANG, DUN. MORI , J IM. UCHIDE, TAKAHIKO. 2012. SUPERSHEAR RUPTURE ON MULTIPLE FAULTS FOR THE MW 8.6 OFF NORTHERN SUMATRA, INDONESIA EARTHQUAKE OF APRIL 11, 2012. GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L21307

Plate Tectonic Configuration in Indonesia

• Indonesia is located on the meeting point of active tectonic plates. The three most important plates affecting the Indonesian region are the South East-Asian Plate, the IndoAustralian Plate, and the Pacific Plate.

• Faults and shear zones are common in the tectogene parts of Indonesia.

• Most of these subduction- and collision zones are active and characterized by great sub-marine and sub-aerial relief amplitudes.

Maps of Eartquake Zone in Indonesia

Ministry of public works

Acceleration spectra for 1s in bed rocks (dumping ratio 5%) in 50 years

List of recent big earthquake occurrences in Indonesia (most of them are happened on seas)

November 15, 2014 – Molucca Sea (Mw 7.1)

April 11, 2012 – Nothern Sumatera (Mw 8.6)

October 25, 2010 – Mentawai produced Tsunami (Mw 7.8)

December 2004 – Banda Aceh, Sumatera , produced Tsunami (Mw 8.7)

December 12, 1992 – Flores Seaproduced Tsunami (Mw 7.9)

Case StudyMolucca Sea (Mw 7.1)

Earthquake location

Gray dots : the locations of aftershocks. Red triangles : the location of the GPS

The focal mechanism for the earthquake indicates reverse faulting, dipping either steeply towards the northwest, or more gently towards the southeast,

Case StudyMolucca Sea (Mw 7.1)

Slip parameters used in Molucca Sea, Indonesia, earthquake (MOSEQ) model

Case StudyMolucca Sea (Mw 7.1)

The surface waves traveled the 11.422 km along the perimeter of the earth from the earthquake source to recording station in +/- 4 minutes

Wave forms in calculated (red lines) and obserbved (black line)

Bandpass filter : 0.0125 Hz – 0.040 Hz

Case StudyNothern Sumatera (Mw 8.6)

Rupture propagation and radiated energies of Mw = 8.6 Sumatera earthquakeStimulated in (0-56 s, 56- 100 s, 100-156 s, 156- 180 s)

Maximum stack amplitude in each time window , measured from the epicenter (for the first 100 s), showed in graph of distance and time function

Case StudyMentawai (Mw 7.8)

• GPS observations from the Sumatra GPS Array (SuGAr) network and,based on reconciling both the GPS and tsunami field observations, favoured a narrow patch with ~12m of slip extending 120 km along the shallow fault zone

• Large shallow region slip -> Slow rupture velocity ( 1,25 - 1,5 km/s), long source duration exceeding 110 s (2 mins)

• Localized maximum slip exceeding 4 m near the trench was found in a model by Lay et al. [2011a], and this was shown to be consistent with a deep water tsunami observation at a distant DARTstation, but the spatial resolution was limited.

Case StudyMentawai (Mw 7.8)

• A 105 sub fault parameterization with sub fault areas of 15× 15 km2 for the shallowest updip row. The red dots indicate the subfaults containing the event hypocenter.

• Simulation period : 4 s (for each sub-faults), > 10 s ( for total long fault)

Slip pattern and sub-fault source time functions for inversions with the fine and coarse grids are shown on top and bottom rows, respectively.

Case StudyMentawai (Mw 7.8)

P waves are pressure waves that travel faster than other waves through the earth to arrive at seismograph stations firstly, hence the name "Primary". These waves can travel through any type of material, including fluids, and can travel at nearly twice the speed of S waves

S-waves arrive at seismograph stations after the faster-moving P-waves and displace the ground perpendicular to the direction of propagation

Observed (red) and modeled (black) ground displacement signals for hr-GPS and selected teleseismic P waves and S waves for the preferred fine-grid joint inversion.

120s

Case StudyBanda Aceh, Sumatera , (Mw 8.7)• The 2004 Sumatera-Andaman earthquake is the largest second earthquake after Krakatau rupture in 1883.

• The event caused 1300 km rupture length which consists 7 different segments from northwest Sumatera to Andaman Islands ( more than 1600 km )

• Very long propagation period (TL ) > 600 s

• Caused major structure damaged on thick soft soils

Case StudyBanda Aceh, Sumatera , (Mw 8.7)

• PGA (peak ground acceleration) of incoming wave in rocks < 0.04 g

recorded in soil level station

Tsunami propagation after earthquake (USGS)

Tsunami wave height reach 10-12 m !

Earthquake DamageBanda Aceh, Sumatera

Tsunami wave heightInundation height in landMeulaboh (western coast ) about 4 mLhok Nga (West Banda Aceh) about 15 m Banda Aceh (in coastal areas) about 8 m

(Setiawan, 2013)

Earthquake DamageBanda Aceh, Sumatera

DAMAGES1. Building2. Infrastructures (roads, ports,

power supply, telecommunication, industrial)

(Setiawan, 2013)

Ports at Kreung Raya Ports at Kreung Raya

Power plant damage

Roads damage

• The Team for Revision of Seismic Hazard Maps of Indonesia has produced several new seismic hazard maps for Indonesia in 2010.• This presented seismic hazard maps computed for sites on bed rocks (Vs = 760 m/s) at the 10% PE in 50 years and 2 % PE in 50 years.

Estimates of the ground motions at periods T > 4 sec by consisting a constant-displacement segment, ( 4 s, 6 s, 8 s, 12 s, 16 s, 18 s , 20 s)

Seismic Parameters

TL = the period on the design response spectrum separating the constant-velocity and constant-displacement segments, estimated from strong motion accelerograms with reliable long period content.

TC = the corner period , (approximation calculation for TL), log Tc = -1.25 + 0.3 M

• In areas far from the fault, the magnitude from the subduction control (higher corner period) high TC • For the area far from the fault and subduction (middle value corner period)

Long period transition period (TL) are associated the highest contribution, for the areas near the fault (TC)

Seismic Hazard Maps Result

Miscellaneous

By the recent occurences and evidences of the earthquakes.. We cannot refuse the earthquake, all we have to do is just adjust to it