Earthquakes and tsunamis caused by low-angle normal faulting in the Banda Sea, Indonesia

Cummins, Phil R.; Pranantyo, Ignatius Ryan; Pownall, Jonathan M.; Griffin, Jonathan; Meilano, Irwan; Zhao, Siyuan

doi:10.1038/s41561-020-0545-x

Cited by 33 publications

(39 citation statements)

References 52 publications

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“…In the same way, high‐resolution multibeam bathymetry is providing insights into submarine faults that were previously unknown (D. D. Brothers et al, 2020). For example, Pownall et al (2016) used high‐resolution multibeam data to discover Earth's largest known normal fault, the 450‐km‐long Banda Detachment in eastern Indonesia, now considered the likely source of several damaging historical earthquakes and tsunamis (Cummins et al, 2020).…”

Section: The Problem Of Enigmatic Seismogenic Faults: Where Are Theymentioning

confidence: 99%

Seismic Hazard Analyses From Geologic and Geomorphic Data: Current and Future Challenges

et al. 2020

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The loss of life and economic consequences caused by several recent earthquakes demonstrate the importance of developing seismically safe building codes. The quantification of seismic hazard, which describes the likelihood of earthquake-induced ground shaking at a site for a specific time period, is a key component of a building code, as it helps ensure that structures are designed to withstand the ground shaking caused by a potential earthquake. Geologic or geomorphic data represent important inputs to the most common seismic hazard model (probabilistic seismic hazard analyses, or PSHAs), as they can characterize the magnitudes, locations, and types of earthquakes that occur over long intervals (thousands of years). However, several recent earthquakes and a growing body of work challenge many of our previous assumptions about the characteristics of active faults and their rupture behavior, and these complexities can be challenging to accurately represent in PSHA. Here, we discuss several of the outstanding challenges surrounding geologic and geomorphic data sets frequently used in PSHA. The topics we discuss include how to utilize paleoseismic records in fault slip rate estimates, understanding and modeling earthquake recurrence and fault complexity, the development and use of fault-scaling relationships, and characterizing enigmatic faults using topography. Making headway in these areas will likely require advancements in our understanding of the fundamental science behind processes such as fault triggering, complex rupture, earthquake clustering, and fault scaling. Progress in these topics will be important if we wish to accurately capture earthquake behavior in a variety of settings using PSHA in the future. Plain Language Summary Growing infrastructure and increasing population have caused significant loss of life due to recent large earthquakes, with the 2008 M w 7.9 Wenchuan and 2005 M w 7.6 Kashmir earthquakes each causing greater than 50,000 deaths. These earthquakes highlight the need for the development of building codes designed to withstand the strong ground shaking caused by earthquakes, as reinforced infrastructure is one of the most important factors for preventing fatalities due to ground shaking from earthquakes. Identifying the seismic hazard of a region, or the likelihood of ground shaking at a site due to potential earthquakes over time, is a key ingredient for informing a defensible building code. Here, we focus on current and future advances in how data from the fields of geology and geomorphology contribute to the most widely used type of seismic hazard model. These geologic data represent vital components to seismic hazard models, as they can provide information about the location and types of earthquakes that can occur over long, thousands of years, time periods, that cannot be obtained using other methods. We discuss some of the most pressing scientific issues about these data that are important for the development of seismic hazard models and defensible building codes.

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Section: The Problem Of Enigmatic Seismogenic Faults: Where Are Theymentioning

confidence: 99%

Seismic Hazard Analyses From Geologic and Geomorphic Data: Current and Future Challenges

et al. 2020

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“…In addition to these two primary reasons, we note that the 1938 Mw = 8.4 earthquake (Okal & Reymond, 2003) was very nearly in the same location as the proposed landslide source in (Cummins et al, 2020), yet there is no evidence of a submarine slump occurring as a result. This makes it less likely that the earthquake source proposed in (Cummins et al, 2020) may have induced a slump sufficient to yield the recorded tsunami.…”

Section: Available Observational Data and Previous Modeling For The 1mentioning

confidence: 82%

“…In addition, although this article focuses on mega‐thrust events, the methodology is sufficiently flexible to work for a submarine slump induced tsunami, or any other type of hazard for which a forward model is available. We will look into these possibilities in future studies, including analyzing the potential for the 1852 event to have been caused by a submarine slump as suggested by (Cummins et al., 2020; Pranantyo & Cummins, 2020).…”

Section: Discussion and Future Workmentioning

confidence: 99%

Methodological Reconstruction of Historical Seismic Events From Anecdotal Accounts of Destructive Tsunamis: A Case Study for the Great 1852 Banda Arc Mega‐Thrust Earthquake and Tsunami

et al. 2021

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We demonstrate the efficacy of a Bayesian statistical inversion framework for reconstructing the likely characteristics of large pre‐instrumentation earthquakes from historical records of tsunami observations. Our framework is designed and implemented for the estimation of the location and magnitude of seismic events from anecdotal accounts of tsunamis including shoreline wave arrival times, heights, and inundation lengths over a variety of spatially separated observation locations. The primary advantage of this approach is that all of the assumptions made in the inversion process are incorporated explicitly into the mathematical framework. As an initial test case we use our framework to reconstruct the great 1852 earthquake and tsunami of eastern Indonesia. Relying on the assumption that these observations were produced by a subducting thrust event, the posterior distribution indicates that the observables were the result of a massive mega‐thrust event with magnitude near 8.8 Mw and a likely rupture zone in the north‐eastern Banda arc. The distribution of predicted epicentral locations overlaps with the largest major seismic gap in the region as indicated by instrumentally recorded seismic events. These results provide a geologic and seismic context for hazard risk assessment in coastal communities experiencing growing population and urbanization in Indonesia. In addition, the methodology demonstrated here highlights the potential for applying a Bayesian approach to enhance understanding of the seismic history of other subduction zones around the world.

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“…Offset geomorphic features, such as river streams and shutter ridges along this fault and the nearby Tehoru 1899 M7.8 tsunamigenic earthquake, all indicate that the Kawa shear zone has been active during Quaternary and is capable of generating large earthquakes (Brune et al, 2010;. Furthermore, the Banda detachment has also been suggested to have caused destructive earthquakes, earthquake induced submarine landslides which in turn triggered large tsunamis (Cummins et al, 2020). In contrast, the Kumawa fault is a shallow crustal fault rooted at plate interface (Figures 3 and 4).…”

Section: The Extent Of the Seram-kumawa Shear Zonementioning

confidence: 97%

The Margin‐Oblique Kumawa Strike‐Slip Fault in the Banda Forearc, East Indonesia: Structural Deformation, Tectonic Origin and Geohazard Implication

2021

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An oceanic plate subduction along active margins is often accompanied by oblique convergence with obliquity increasing away from the subduction center (Philippon & Corti, 2016), for example, Banda, Sumatra, Caribbean, Marianas, Hikurangi, Alentian, Hellenic, etc. The slip vector oblique to such margins is partitioned into a dip-slip, the orthogonal component, responsible for under-thrusting in the subduction zones and a strike-slip component responsible for transcurrent motions parallel to the margin on the upper plate

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Earthquakes and tsunamis caused by low-angle normal faulting in the Banda Sea, Indonesia

Cited by 33 publications

References 52 publications

Seismic Hazard Analyses From Geologic and Geomorphic Data: Current and Future Challenges

Seismic Hazard Analyses From Geologic and Geomorphic Data: Current and Future Challenges

Methodological Reconstruction of Historical Seismic Events From Anecdotal Accounts of Destructive Tsunamis: A Case Study for the Great 1852 Banda Arc Mega‐Thrust Earthquake and Tsunami

The Margin‐Oblique Kumawa Strike‐Slip Fault in the Banda Forearc, East Indonesia: Structural Deformation, Tectonic Origin and Geohazard Implication

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