Migration of seismicity and earthquake interactions monitored by GPS in SE Asia triple junction: Sulawesi, Indonesia

Vigny, Christophe; Perfettini, H.; Walpersdorf, Andréa; Lemoine, Anne; Simons, Wim; Loon, Danny van; Ambrosius, B. A. C.; Stevens, C.; McCaffrey, R.; Morgan, Peter; Bock, Yehuda; Subarya, C.; Manurung, Parluhutan; Kahar, Joenil; Abidin, Hasanuddin Z.; Abu, Samad

doi:10.1029/2001jb000377

Cited by 47 publications

(47 citation statements)

References 22 publications

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“…Geological investigations, geomorphic and GPS observations (Socquet et al, ; Walpersdorf, Vigny, et al, ) confirmed that the PKF is a fast moving fault with a relatively low level of seismicity. Since 1 January 1996 when an earthquake sequence was initiated by the Mw 7.9 Tomini earthquake along the Minahassa thrust (Vigny et al, ), the seismicity near the PKF began to be active gradually.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…Although the triple junction zone is highly seismically active, the seismic records show a low level of shallow seismicity in central Sulawesi (Bellier et al, ; McCaffrey & Sutardjo, ). Contrary to the low seismicity, geomorphic and tectonic studies gave a high long‐term slip rate, up to ~40 mm/year, on the PKF (Bellier et al, ; Stevens et al, ; Vigny et al, ; Walpersdorf, Rangin, et al, ; Walpersdorf, Vigny, et al, ). The present‐day GPS measurements provided a similar estimate of slip rate, but the motion is distributed on four parallel strands across a broad zone 50 km to the east (Socquet et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Geodetic Observations of the 2018 Mw 7.5 Sulawesi Earthquake and Its Implications for the Kinematics of the Palu Fault

Song

Zhang

Shan

et al. 2019

Geophysical Research Letters

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The ascending and descending interferometric synthetic aperture radar data are used to investigate the fault rupture and slip model of the 2018 Mw 7.5 Sulawesi, Indonesia, earthquake. The best fitting slip model indicates that this earthquake ruptured not only a segment extending the Palu fault to the north but also a northwestern segment offshore. The slip on the onshore fault is predominant left‐lateral strike slip. The slip on the offshore fault is dominated by normal faulting with a maximum slip of ~6.3 m. The newly discovered offshore normal faulting is likely to be the cause of the tsunami after the shock. Combined with previous geomorphic, tectonic, geodetic, and modeling studies, we suggest that the kinematics of the Palu fault maintained the same style of faulting from north to south, which resulted from an oblique extension occurred on an east dipping fault at depths. The deformation pattern of NW Sulawesi is dominated by this slip mechanism.

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Section: Tectonic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geodetic Observations of the 2018 Mw 7.5 Sulawesi Earthquake and Its Implications for the Kinematics of the Palu Fault

Song

Zhang

Shan

et al. 2019

Geophysical Research Letters

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“…The inter-seismic stress accumulation rate distribution along the entire Palu-Koro fault remains unclear. However, Vigny et al (2002) calculated the maximum principal horizontal strain rate of about 311 and -291 nanostrain/a oriented 113°(±2°) using the geodetic data obtained on the Palu-Koro fault in the Palu basin. Based on this estimation, we could deduce a maximum principal stress rate of 3.11 and -2.91 kPa/a on the Palu-Koro fault assuming an elastic modulus of 1.0×10 10 Pa. By integrating a roughly estimated tectonic loading Coulomb stress rate of approximately 1.0 kPa/a (approximately one third of the maximum principal stress rate), the promoted ΔCFS (51 kPa) was consistent with tectonic loading over approximately 51 years.…”

Section: Discussionmentioning

confidence: 99%

“…Sulawesi Island moves northwestward following clockwise rotation about 4°/Ma. In comparison, the Australian plate drifts northward, the Philippine Sea plate moves westward, and Sunda plate blocks the west (Vigny et al, 2002;Socquet et al, 2006). The Celebes Sea floor subducts the northern region beneath Sulawesi, and the Minahassa trench accommodates the northwestward movements of the Sula block relative to the Sunda plate (Socquet et al, 2006).…”

Section: Geological Settingmentioning

confidence: 99%

Stress partition on the Palu-Koro fault controlling the 2018 Mw 7.5 Palu earthquake and its seismic hazards

Liu¹,

Shi²

2020

Preprint

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The Mw 7.5 Palu earthquake struck the Palu-Koro fault on September 28, 2018 in the Sulawesi Island, Indonesia. Previous studies suggested that the predominantly unilateral southward rupture of this earthquake unzipped the central part of the Palu-Koro fault. Two seismic gaps were left to the north and south ends of the Palu-Koro fault. To date, the cause for earthquake generation has yet to be investigated. As a result, the reasons behind the earthquake rupture's southward unilateral propagation and termination remain unclear. The hazards of the two seismic gaps at the north and south ends of the Palu-Koro fault have yet to be explored. As such, the present study calculated the Coulomb stress change that was induced by historical large earthquakes within the target region. The stress partition and evolution on the Palu-Koro fault were examined before and after the 2018 Palu earthquake. We found that the 1996 earthquake (Mw = 7.9) on the Minahassa thrust triggered the 2018 Palu earthquake by promoting stress at the epicenter of the 2018 earthquake. The stress shadow close to the north of the epicenter of the earthquake acted as a stress barrier by preventing the earthquake northward rupture. However, the southward earthquake propagation was terminated by the stress shadow to the south of the rupture. These stress shadows were caused by the historical earthquakes on the Palu-Koro fault. Stress promotions in the two seismic gaps of the Palu-Koro fault produced by 2018 Palu earthquake have resulted in increased seismic and tsunami hazards, calling close attention to hazard prevention in central Sulawesi. Our results are important for understanding the stress migration and the induced seismic activity in the thrust and strike-slip faults system globally.

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“…A number of crustal blocks take part in this rotation, the Makassar block in SW Sulawesi, the North Sula block, the Manado block and the East Sula block in NE Sulawesi (Figure 7c). Walpersdorf et al [1998] indicate a location of plate intersection in the southern Molucca Sea (represented by a star in Figure 7c), although the convergence area has a 500 km diameter in total [ Vigny et al , 2002]. …”

Section: Tsunami Hazard Methodology and Scenario Descriptionsmentioning

confidence: 99%

Historical tsunamis and present tsunami hazard in eastern Indonesia and the southern Philippines

Løvholt¹,

Kühn²,

Bungum³

et al. 2012

J. Geophys. Res.

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[1] Eastern Indonesia and the southern Philippines comprise a huge and seismically highly active region that has received less than the deserved attention in tsunami research compared with the surrounding areas exposed to the major subduction zones. In an effort to redress the balance the tsunami hazard in this region is studied by establishing a tsunami event database which, in combination with seismological and tectonic information from the region, has allowed us to define and justify a number of 'credible worst-case' tsunami scenarios. These scenarios have been used in numerical simulations of tsunami generation and propagation to study maximum water level along potentially affected shorelines. The scenarios have in turn been combined to provide regional tsunami hazard maps. In many cases the simulations indicate that the maximum water level may exceed 10 m locally and even reach above 20 m in the vicinity of the source, which is of the same order as what is forecasted along the Sumatra and Java trenches for comparable return periods. For sections of coastlines close to a source, a tsunami may strike only a few minutes after it is generated, providing little time for warning. Moreover, several of the affected areas are highly populated and are therefore also high risk areas. The combination of high maximum water levels, short warning times, dense populations, and relatively short return periods suggests strongly that the tsunami hazard and risk in these regions are alarmingly high.

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Migration of seismicity and earthquake interactions monitored by GPS in SE Asia triple junction: Sulawesi, Indonesia

Cited by 47 publications

References 22 publications

Geodetic Observations of the 2018 Mw 7.5 Sulawesi Earthquake and Its Implications for the Kinematics of the Palu Fault

Geodetic Observations of the 2018 Mw 7.5 Sulawesi Earthquake and Its Implications for the Kinematics of the Palu Fault

Stress partition on the Palu-Koro fault controlling the 2018 Mw 7.5 Palu earthquake and its seismic hazards

Historical tsunamis and present tsunami hazard in eastern Indonesia and the southern Philippines

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