scholarly journals Indonesian Throughflow as a preconditioning mechanism for submarine landslides in the Makassar Strait

2020 ◽  
Vol 500 (1) ◽  
pp. 195-217 ◽  
Author(s):  
Rachel E. Brackenridge ◽  
Uisdean Nicholson ◽  
Benyamin Sapiie ◽  
Dorrik Stow ◽  
Dave R. Tappin
Keyword(s):  
Mass Transport ◽  
Conveyor Belt ◽  
Ocean Current ◽  
Indonesian Throughflow ◽  
Submarine Landslides ◽  
Fault Rupture ◽  
The South ◽  
The Pacific ◽  
The Indian Ocean ◽  
Mass Transport Deposits

AbstractThe Makassar Strait is an important oceanic gateway, through which the main branch of the Indonesian Throughflow (ITF) transports water from the Pacific to the Indian Ocean. This study identifies a number of moderate (>10 km3) to giant (up to 650 km3) mass transport deposits within the Makassar North Basin Pleistocene–Recent section. The majority of submarine landslides that formed these deposits originated from the Mahakam pro-delta, with the largest skewed to the south. We see clear evidence for ocean-current erosion, lateral transport and contourite deposition across the upper slope. This suggests that the ITF is acting as an along-slope conveyor belt, transporting sediment to the south of the delta, where rapid sedimentation rates and slope oversteepening results in recurring submarine landslides. A frequency for the >100 km3 failures is tentatively proposed at 0.5 Ma, with smaller events occurring at least every 160 ka. This area is therefore potentially prone to tsunamis generated from these submarine landslides. We identify a disparity between historical fault rupture-triggered tsunamis (located along the Palu-Koro fault zone) and the distribution of mass transport deposits in the subsurface. If these newly identified mass failures are tsunamigenic, they may represent a previously overlooked hazard in the region.

scholarly journals The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport in the South Atlantic

2011 ◽  
Vol 41 (8) ◽  
pp. 1498-1511 ◽  
Author(s):  
Shenfu Dong ◽  
Silvia Garzoli ◽  
Molly Baringer
Keyword(s):  
Indian Ocean ◽  
Heat Transport ◽  
South Atlantic ◽  
Similar Response ◽  
The South ◽  
Meridional Heat Transport ◽  
Interior Region ◽  
The Pacific ◽  
The Indian Ocean

Abstract The interocean exchange of water from the South Atlantic with the Pacific and Indian Oceans is examined using the output from the ocean general circulation model for the Earth Simulator (OFES) during the period 1980–2006. The main objective of this paper is to investigate the role of the interocean exchanges in the variability of the Atlantic meridional overturning circulation (AMOC) and its associated meridional heat transport (MHT) in the South Atlantic. The meridional heat transport from OFES shows a similar response to AMOC variations to that derived from observations: a 1 Sv (1 Sv ≡ 106 m3 s−1) increase in the AMOC strength would cause a 0.054 ± 0.003 PW increase in MHT at approximately 34°S. The main feature in the AMOC and MHT across 34°S is their increasing trends during the period 1980–93. Separating the transports into boundary currents and ocean interior regions indicates that the increase in transport comes from the ocean interior region, suggesting that it is important to monitor the ocean interior region to capture changes in the AMOC and MHT on decadal to longer time scales. The linear increase in the MHT from 1980 to 1993 is due to the increase in advective heat converged into the South Atlantic from the Pacific and Indian Oceans. Of the total increase in the heat convergence, about two-thirds is contributed by the Indian Ocean through the Agulhas Current system, suggesting that the warm-water route from the Indian Ocean plays a more important role in the northward-flowing water in the upper branch of the AMOC at 34°S during the study period.

scholarly journals POTENSI ENERGI ARUS LAUT SEBAGAI ENERGI TERBARUKAN DI SELAT LOMBOK BERDASARKAN DATA INSTANT WEST MOORING DEPLOYMENT 1

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Yogo Pratomo ◽  
Widodo Setiyo Pranowo ◽  
Sahat Monang Simanjuntak
Keyword(s):  
Renewable Energy ◽  
Water Depth ◽  
Current Speed ◽  
Ocean Currents ◽  
Ocean Current ◽  
The Pacific ◽  
Through Flow ◽  
The Indian Ocean ◽  
The Pacific Ocean ◽  
Harmonic Components

Selat Lombok merupakan salah satu perlintasan massa air laut dunia, yang mengalir dari Samudera Pasifik menuju ke Samudera Hindia yang disebut sebagai Arus Lintas Indonesia (ARLINDO). Hal ini terbukti dengan adanya komponen harmonik periode panjang yang di pengaruhi oleh Matahari (SA, SSA), dan dipengaruhi Bulan (MSF). Hasil rekaman mooring selama 1,5 tahun, selat ini memiliki kecepatan arus harmonik rata-rata sebesar 0,25219 m/dt di kedalaman 100 meter. Arus laut merupakan salah satu energi baru terbarukan yang dapat di manfaatkan sebagai pembangkit listrik. Arus laut diolah dengan menggunakan modul toolbox T-Tide 1,3 beta, dan menghasilkan arus harmonik dan arus non harmonik. Berdasarkan komputasi skenario pertama, dengan menggunakan turbin Helix LC 500 dan menghasilkan listrik 3,56 KW (harmonic), dan 1,86 KW (non harmonik) dengan kecepatan arus terbesar terjadi pada kedalaman 146,31 meter. Nilai kecepatan arus rata-rata terdapat pada kedalaman 178,31 meter dengan daya yang dihasilkan sebesar 92,17 W pada kondisi arus non harmonik. Kecepatan arus rata-rata pada kondisi arus harmonik terdapat pada kedalaman 162,31 meter, dengan daya yang dihasilkan sebesar 32,943 W.Kata Kunci : arus laut, energi baru terbarukan, Selat Lombok, INSTANT West Mooring.Lombok Strait is one of seawater mass outlet, flowing from the Pacific Ocean toward the Indian Ocean called as Indonesian Through Flow (ITF). It is proven by long period of harmonic components influenced by sun (SA, SSA) and moon (MSF). The result of mooring record for 1.5 years, this strait has average speed of the harmonic ocean current is 0.25219 m/s at 100 meters water depth. Ocean current is one of renewable energy that can be used for generating power electric. Ocean currents processed by using T-tide matlab toolbox 1.3 beta to identified the harmonic and non harmonic currents. Based on first scenario of the computer conversion, by using a Helix turbine LC 500 and produce an electricity energy about 3.56 KW (harmonic), and 1.86 KW (non harmonic) ocean currents, with the maximum current speed at the 146.31 meters water depth. The average of current speed average found at 178.31 meters water depth, and it produces a power of 92.17 W (non harmonic). The current speed averages from the harmonic condition is found at 162.31 meters water depth, which can produce a power about 32.943 W.Keyword : ocean currents, potential renewable energy, Lombok Strait, INSTANT West Mooring.

scholarly journals On the Indonesian throughflow in the OCCAM 1/4 degree ocean model

2007 ◽  
Vol 4 (2) ◽  
pp. 325-370 ◽  
Author(s):  
U. W. Humphries ◽  
D. J. Webb
Keyword(s):  
Indian Ocean ◽  
Ocean Model ◽  
Global Ocean ◽  
Indonesian Throughflow ◽  
Island Rule ◽  
Near Surface ◽  
The North ◽  
The Pacific ◽  
The Indian Ocean ◽  
Pass Through

Abstract. The Indonesian Throughflow is analysed in two runs of the OCCAM 1/4 degree global ocean model, one using monthly climatological winds and one using ECMWF analysed six-hourly winds for the period 1993 to 1998. The long-term model throughflow agrees with observations and the value predicted by Godfrey's Island Rule. The Island Rule has some skill in predicting the annual signal each year but is poor at predicting year to year and shorter term variations in the total flow especially in El Nino years. The spectra of transports in individual passages show significant differences between those connecting the region to the Pacific Ocean and those connecting with the Indian Ocean. This implies that different sets of waves are involved in the two regions. Vertical profiles of transport are in reasonable agreement with observations but the model overestimates the near surface transport through the Lombok Strait and the dense overflow from the Pacific through the Lifamatola Strait into the deep Banda Sea. In both cases the crude representation of the passages by the model appears responsible. In the north the model shows, as expected, that the largest transport is via the Makassar Strait. However this is less than expected and instead there is significant flow via the Halmahera Sea. If Godfrey's Island Rule is correct and the throughflow is forced by the northward flow between Australia and South America, then the Halmahers Sea route should be important. It is the most southerly route around New Guinea to the Indian Ocean and there is no apparent reason why the flow should go further north in order to pass through the Makassar Strait. The model result thus raises the question of why in reality the Makassar Strait route appears to dominate the throughflow.

scholarly journals On the Indonesian Throughflow in the OCCAM 1/4 degree ocean model

Ocean Science ◽  
2008 ◽  
Vol 4 (3) ◽  
pp. 183-198 ◽  
Author(s):  
U. W. Humphries ◽  
D. J. Webb
Keyword(s):  
Indian Ocean ◽  
Ocean Model ◽  
Global Ocean ◽  
Indonesian Throughflow ◽  
Island Rule ◽  
Near Surface ◽  
The North ◽  
The Pacific ◽  
The Indian Ocean ◽  
Pass Through

Abstract. The Indonesian Throughflow is analysed in two runs of the OCCAM 1/4 degree global ocean model, one using monthly climatological winds and one using ECMWF analysed six-hourly winds for the period 1993 to 1998. The long-term model throughflow agrees with observations and the value predicted by Godfrey's Island Rule. The Island Rule has some skill in predicting the annual signal each year but is poor at predicting year to year and shorter term variations in the total flow, especially in El Niño years. The spectra of transports in individual passages show significant differences between those connecting the region to the Pacific Ocean and those connecting with the Indian Ocean. On investigation we found that changes in the northern transports were strongly correlated with changes in the position of currents in the Celebes Sea and off Halmahera. Vertical profiles of transport are in reasonable agreement with observations but the model overestimates the near surface transport through the Lombok Strait and the dense overflow from the Pacific through the Lifamatola Strait into the deep Banda Sea. In both cases the crude representation of the passages by the model appears responsible. In the north the model shows, as expected, that the largest transport is via the Makassar Strait. However this is less than expected and instead there is significant flow via the Halmahera Sea. If Godfrey's Island Rule is correct and the throughflow is forced by the northward flow between Australia and South America, then the Halmahers Sea route should be important. It is the most southerly route around New Guinea to the Indian Ocean and there is no apparent reason why the flow should go further north in order to pass through the Makassar Strait. The model result thus raises the question of why in reality the Makassar Strait route appears to dominate the throughflow.

Indo-Pacific Climate Interactions in the Absence of an Indonesian Throughflow

2015 ◽  
Vol 28 (13) ◽  
pp. 5017-5029 ◽  
Author(s):  
Jules B. Kajtar ◽  
Agus Santoso ◽  
Matthew H. England ◽  
Wenju Cai
Keyword(s):  
Indian Ocean ◽  
Climate Model ◽  
Southern Oscillation ◽  
Ocean Basin ◽  
Climate System ◽  
Indonesian Throughflow ◽  
Enso Events ◽  
The Pacific ◽  
The Indian Ocean ◽  
Mean Climate

Abstract The Pacific and Indian Oceans are connected by an oceanic passage called the Indonesian Throughflow (ITF). In this setting, modes of climate variability over the two oceanic basins interact. El Niño–Southern Oscillation (ENSO) events generate sea surface temperature anomalies (SSTAs) over the Indian Ocean that, in turn, influence ENSO evolution. This raises the question as to whether Indo-Pacific feedback interactions would still occur in a climate system without an Indonesian Throughflow. This issue is investigated here for the first time using a coupled climate model with a blocked Indonesian gateway and a series of partially decoupled experiments in which air–sea interactions over each ocean basin are in turn suppressed. Closing the Indonesian Throughflow significantly alters the mean climate state over the Pacific and Indian Oceans. The Pacific Ocean retains an ENSO-like variability, but it is shifted eastward. In contrast, the Indian Ocean dipole and the Indian Ocean basinwide mode both collapse into a single dominant and drastically transformed mode. While the relationship between ENSO and the altered Indian Ocean mode is weaker than that when the ITF is open, the decoupled experiments reveal a damping effect exerted between the two modes. Despite the weaker Indian Ocean SSTAs and the increased distance between these and the core of ENSO SSTAs, the interbasin interactions remain. This suggests that the atmospheric bridge is a robust element of the Indo-Pacific climate system, linking the Indian and Pacific Oceans even in the absence of an Indonesian Throughflow.

Tectonic and geomorphic controls on the distribution of submarine landslides across active and passive margins, eastern New Zealand

2020 ◽  
Author(s):  
Sally Watson ◽  
Joshu Mountjoy ◽  
Gareth Crutchley
Keyword(s):  
New Zealand ◽  
Mass Transport ◽  
Submarine Landslide ◽  
Sediment Supply ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
Active Margin ◽  
Eastern Margin ◽  
Marine Habitats ◽  
Mass Transport Deposits

<p>Submarine landslides occur on continental margins globally and can have devastating consequences for marine habitats, offshore infrastructure and coastal communities due to potential tsunamigenic consequences. Evaluation of the magnitude and distribution of submarine landslides is central to marine and coastal hazard planning. Despite this, there are few studies that comprehensively quantify the occurrence of submarine landslides on a margin-wide scale.</p><p> </p><p>We present the first margin-wide submarine landslide database along the eastern margin of New Zealand comprising >2200 landslide scars and associated mass-transport deposits. Analysis of submarine landslide distribution reveals 1) locations prone to mass-failure, 2) spatial patterns of landslide scale and occurrence, and 3) the potential preconditioning factors and triggers of mass wasting across different geologic settings.</p><p> </p><p>Submarine landslides are widespread on the eastern margin of New Zealand, occurring in water depths from ~300 m to ~4,000 m. Landslide scars and mass transport deposits are more prevalent, and on average larger, on the active margin, compared the passive margin. We attribute higher concentrations of landslides on the active margin to the prevalence of deforming thrust ridges, related to active margin processes including oversteepening, faulting and seamount subduction. Higher sediment supply on the northernmost active margin is also likely to be a key preconditioning factor resulting in the concentration of large landslides in this region.</p><p> </p><p>In general, submarine landslide scars are concentrated around canyon systems and close to canyon thalwegs. This suggests that not only does mass wasting play a major role in canyon evolution, but also that slope undercutting in canyons may be a fundamental preconditioning factor for slope failure.</p><p> </p><p>Results of this study offer unique insights into the spatial distribution, magnitude and morphology of submarine landslides across different geologic settings, providing a better understanding of the causative factors for mass wasting in New Zealand and around the world.</p><p> </p>

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