scholarly journals Tsunami Wave Analysis and Possibility of Splay Fault Rupture During the 2004 Indian Ocean Earthquake

2011 ◽  
Vol 169 (10) ◽  
pp. 1707-1735 ◽  
Author(s):  
Nora DeDontney ◽  
James R. Rice
Keyword(s):  
Indian Ocean ◽  
Tsunami Wave ◽  
Fault Rupture ◽  
Wave Analysis ◽  
Splay Fault

The effect of multiple splay fault rupture on tsunamis

2020 ◽  
Author(s):  
Iris van Zelst ◽  
Leonhard Rannabauer ◽  
Alice-Agnes Gabriel ◽  
Ylona van Dinther
Keyword(s):  
Vertical Surface ◽  
Tsunami Hazard ◽  
Fault Rupture ◽  
Geophysical Research ◽  
Large Wave ◽  
Surface Displacements ◽  
Seismic Cycles ◽  
Splay Faults ◽  
Splay Fault ◽  
The Waves

<p>Earthquake rupture on splay faults in subduction zones could pose a significant tsunami hazard, as they could accommodate more vertical displacement and are situated closer to the coast. To better understand this tsunami hazard, we model splay fault rupture dynamics and tsunami propagation and inundation constrained by a geodynamic seismic cycle (SC) model; building on work presented in Van Zelst et al. (2019). This two-dimensional modelling framework considers geodynamics, seismic cycles, dynamic ruptures, and tsunamis together for the first time. The SC model provides six blind splay fault geometries, self-consistent stress and strength conditions, and heterogeneous material properties in the domain. We find that all six splay faults are activated when the megathrust ruptures. The largest splay fault closest to the nucleation region ruptures immediately when the main rupture front passes the branching point. The other splay faults are activated through dynamic stress transfer from the main megathrust rupture or reflected waves from the surface. Splay fault rupture results in distinct peaks in the vertical surface displacements with a smaller wavelength and larger amplitudes. The effect of the vertical surface displacements also translates into the resulting tsunami, which consists of one large wave for the megathrust-only model and seven waves for the model including splay faults. Here, six of the waves can be attributed to the splay faults and the seventh wave results from the shallow tip of the megathrust. The waves from the rupture including splay faults have larger amplitudes and result in two episodes of coastal flooding. The first episode is due to the large wave caused by rupture on the largest splay fault nearest to the coast. The second flooding episode results from the combination and interference of the waves caused by the rest of the splay faults and the shallow megathrust tip. In contrast, the tsunami caused by rupture on only the megathrust has only one episode of flooding. Our results suggest that larger-than-expected tsunamis could be attributed to rupture on large splay faults. When multiple smaller splay faults rupture their effect on the tsunami might be hard to distinguish from a pure megathrust rupture. Considering the significant effects splay fault rupture can have on a tsunami, it is important to understand splay fault activation and to consider them in hazard assessment.</p><p>References:</p><p>Van Zelst, I., Wollherr, S., Madden, E. H. , Gabriel, A.-A., and Van Dinther, Y. (2019). Modeling megathrust earthquakes across scales: one-way coupling from geodynamics and seismic cycles to dynamic rupture. Journal of Geophysical Research: Solid Earth, 124, https://doi.org/10.1029/2019JB017539</p><p></p>

Landscape Changes in the Andaman and Nicobar Islands (India) after the December 2004 Great Sumatra Earthquake and Indian Ocean Tsunami

2006 ◽  
Vol 22 (3_suppl) ◽  
pp. 43-66 ◽  
Author(s):  
Javed N. Malik ◽  
C. V. R. Murty ◽  
Durgesh C. Rai
Keyword(s):  
Indian Ocean ◽  
Built Environment ◽  
Plate Tectonics ◽  
Tsunami Wave ◽  
Indian Ocean Tsunami ◽  
Sumatra Earthquake ◽  
Landscape Changes ◽  
Andaman And Nicobar Islands ◽  
Nicobar Islands ◽  
Reconnaissance Surveys

Plate tectonics after the 26 December 2004 Great Sumatra earthquake resulted in major topological changes in the Andaman and Nicobar islands. Aerial and land reconnaissance surveys of those islands after the earthquake provide evidence of spectacular plate tectonics that took place during the earthquake. Initial submergence of the built environment and the subsequent inundation upon arrival of the tsunami wave, as well as emergence of the new beaches along the islands—particularly on the western rims of the islands and in the northern islands—are the major signatures of this Mw=9.3 event.

Tsunami Hazards in the Northwestern Indian Ocean

2008 ◽  
Author(s):  
Mohammad Heidarzadeh ◽  
Moharram D. Pirooz ◽  
Nasser H. Zaker
Keyword(s):  
Indian Ocean ◽  
Tsunami Wave ◽  
Research Work ◽  
Tsunami Hazard ◽  
Deterministic Method ◽  
The Past ◽  
Preliminary Estimation ◽  
Historical Tsunami ◽  
Tsunami Hazard Assessment ◽  
Wave Heights

Although northwestern Indian Ocean has experienced some deadly tsunamis in the past, this region remains one of the least studied regions in the world and little research work has been devoted to its tsunami hazard assessment. In this study, we compile and analyze historical tsunami in the northwestern Indian Ocean and present a tsunami list for this region. Then, a deterministic method has been employed to give a preliminary estimation of the tsunami hazard faced by different coastlines in this region. Different source scenarios are considered and for each scenario, numerical modeling of tsunami is performed. For each case, the maximum positive tsunami wave heights along the coasts are calculated which provide a preliminary estimation of tsunami hazard and show which locations face the greatest threat from a large tsunami.

scholarly journals A 1000-yr-old tsunami in the Indian Ocean points to greater risk for East Africa

Geology ◽  
2020 ◽  
Vol 48 (8) ◽  
pp. 808-813 ◽  
Author(s):  
Vittorio Maselli ◽  
Davide Oppo ◽  
Andrew L. Moore ◽  
Aditya Riadi Gusman ◽  
Cassy Mtelela ◽  
...  
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Tsunami Wave ◽  
Research Effort ◽  
Sedimentary Facies ◽  
Western Indian Ocean ◽  
Eastern Indian Ocean ◽  
Tsunami Source ◽  
Recurrence Time ◽  
Sand Layer

Abstract The December 2004 Sumatra-Andaman tsunami prompted an unprecedented research effort to find ancient precursors and quantify the recurrence time of such a deadly natural disaster. This effort, however, has focused primarily along the northern and eastern Indian Ocean coastlines, in proximal areas hardest hit by the tsunami. No studies have been made to quantify the recurrence of tsunamis along the coastlines of the western Indian Ocean, leading to an underestimation of the tsunami risk in East Africa. Here, we document a 1000-yr-old sand layer hosting archaeological remains of an ancient coastal Swahili settlement in Tanzania. The sedimentary facies, grain-size distribution, and faunal assemblages indicate a tsunami wave as the most likely cause for the deposition of this sand layer. The tsunami in Tanzania is coeval with analogous deposits discovered at eastern Indian Ocean coastal sites. Numerical simulations of tsunami wave propagation indicate a megathrust earthquake generated by a large rupture of the Sumatra-Andaman subduction zone as the likely tsunami source. Our findings provide evidence that teletsunamis represent a serious threat to coastal societies along the western Indian Ocean, with implications for future tsunami hazard and risk assessments in East Africa.

scholarly journals Tsunami records of the last 8000 years in the Andaman Island, India, from mega and large earthquakes: Insights on recurrence interval

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Javed N. Malik ◽  
Frango C. Johnson ◽  
Afzal Khan ◽  
Santiswarup Sahoo ◽  
Roohi Irshad ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Fault Rupture ◽  
Andaman Island ◽  
Large Magnitude ◽  
The Past ◽  
The One ◽  
Andaman Earthquake ◽  
2004 Tsunami ◽  
Large Earthquakes ◽  
Sand Sheets

AbstractAs many as seven tsunamis from the past 8000 years are evidenced by sand sheets that rest on buried wetland soils at Badabalu, southern Andaman Island, along northern part of the fault rupture of the giant 2004 Aceh-Andaman earthquake. The uppermost of these deposits represents the 2004 tsunami. Underlying deposits likely correspond to historical tsunamis of 1881, 1762, and 1679 CE, and provide evidence for prehistoric tsunamis in 1300–1400 CE, in 2000–3000 and 3020–1780 BCE, and before 5600–5300 BCE. The sequence includes an unexplained hiatus of two or three millennia ending around 1400 CE, which could be attributed to accelerated erosion due to Relative Sea-Level (RSL) fall at ~3500 BP. A tsunami in 1300–1400, comparable to the one in 2004, was previously identified geologically on other Indian Ocean shores. The tsunamis assigned to 1679, 1762, and 1881, by contrast, were more nearly confined to the northeast Indian Ocean. Sources have not been determined for the three earliest of the inferred tsunamis. We suggest a recurrence of 420–750 years for mega-earthquakes having different source, and a shorter interval of 80–120 years for large magnitude earthquakes.

Excitation Process of the 2004 Indian Ocean Tsunami Determined from Seismic Fault Rupture

2006 ◽  
Vol 1 (1) ◽  
pp. 136-141
Author(s):  
Hiroyuki Matsumoto ◽  
◽  
Hitoshi Mikada ◽  
Masanori Suzuki ◽  
Keyword(s):  
Indian Ocean ◽  
Dynamic Behavior ◽  
Indian Ocean Tsunami ◽  
Rupture Propagation ◽  
Fault Models ◽  
Fault Rupture ◽  
Excitation Process ◽  
Seismic Fault ◽  
Fault Rupture Propagation ◽  
The Difference

We simulated the tsunami that had took place after the 2004 Sumatra-Andaman earthquake for two fault models - one from teleseismic body wave inversion and the other from tsunami data. After including the dynamic behavior of the seafloor by fault rupture propagation in the tsunami excitation process in detail, we found the difference in tsunami wave heights from the two fault models, in particular due to the difference in slip distribution. We then estimated the effects of the dynamic behavior due to fault rupture propagation, changing the initial conditions of tsunami simulation. Although the effects of dynamic contribution due to seismic fault rupture on tsunami propagating across the Indian Ocean were found to be negligible, the effect of seismic fault rupture propagation contributes to the arrival time of the tsunami because of the huge size of the seismic fault plane. A fault model based on seismic data, however, still cannot explain the tsunami captured by the satellite.

Testing the Synchronicity of Splay-Fault Ruptures in Carson Valley, Nevada, United States

2021 ◽  
Author(s):  
Ian K. D. Pierce ◽  
Steven G. Wesnousky ◽  
Sourav Saha ◽  
Seulgi Moon
Keyword(s):  
Large Earthquake ◽  
Luminescence Dating ◽  
Fault System ◽  
Fault Rupture ◽  
Surface Rupture ◽  
Infrared Stimulated Luminescence ◽  
Structural Relationships ◽  
Splay Fault ◽  
Fault Record ◽  
Age Estimates

ABSTRACT The Carson City and Indian Hills faults in Carson City, Nevada, splay northeastward from the major range-bounding Genoa fault. Each splay is part of the Carson range fault system that extends nearly 100 km northward from near Markleeville, California, to Reno, Nevada. Stratigraphic and structural relationships exposed in paleoseismic excavations across the two faults yield a record of ground-rupturing earthquakes. The most recent on the Carson City fault occurred around 473–311 B.P., with the two penultimate events between 17.9 and 8.1 ka. Two trench exposures across the Indian Hills fault record the most recent earthquake displacement after ∼900 yr, preceded by a penultimate surface rupture ≥∼10,000, based on radiocarbon and infrared-stimulated luminescence dating of exposed sediments. The age estimates allow that the Carson City and Indian Hills faults ruptured simultaneously with a previously reported large earthquake on the Genoa fault ∼514–448 B.P. Similar synchronicity of rupture is not observed in the record of penultimate events. Penultimate ages of ruptures on the Carson City and Indian Hills faults are several thousand years older than that of the Genoa fault from which they splay. Together, these observations imply a variability in rupture moment through time, demonstrating the importance of considering multi-fault rupture models for seismic hazard analyses.

scholarly journals KenSea – tsunami damage modelling for coastal areas of Kenya

2008 ◽  
Vol 15 ◽  
pp. 85-88 ◽  
Author(s):  
John Tychsen ◽  
Ole Geertz-Hansen ◽  
Frands Schjøth
Keyword(s):  
Indian Ocean ◽  
Coastal Area ◽  
Tsunami Wave ◽  
High Tide ◽  
Simulation Modelling ◽  
Coastal Areas ◽  
Eastern Africa ◽  
Tsunami Damage ◽  
Contour Lines ◽  
The Indian Ocean

On 26 December 2004, the eastern part of the Indian Ocean was hit by a tremendous tsunami created by a submarine earthquake of magnitude 9.1 on the Richter scale off the west coast of Sumatra. The tsunami also reached the western part of the Indian Ocean, including the coastal areas of eastern Africa. Along the coast of Kenya (Figs 1, 2) it resulted in a sudden increase in water level comparable to a high tide situation. This rather limited consequence was partly due to the great distance to the epicentre of the earthquake, and partly due to the low tide at the time of the impact. Hence the reefs that fringe two thirds of the coastline reduced the energy of the tsunami waves and protected the coastal areas. During the spring of 2005, staff members from the Geo- logical Survey of Denmark and Greenland (GEUS) carried out field work related to the project KenSea – development of a sensitivity atlas for coastal areas of Kenya (Tychsen 2006; Tychsen et al. 2006). Local fishermen and authorities often asked what would have been the effect if the tsunami had hit the coastal area during a high tide, and to answer the question GEUS and the Kenya Marine and Fisheries Research Institute (KMFRI) initiated a tsunami damage projection project. The aim was to provide an important tool for contingency planning by national and local authorities in the implementation of a national early warning strategy. The tsunami damage projection project used the database of coastal resources – KenSeaBase – that was developed during the KenSea project. The topographical maps of Kenya at a scale of 1:50 000 have 20 m contour lines, which is insufficient for the tsunami run-up simulation modelling undertaken by the new tsunami project. Therefore new sets of aerial photographs were obtained, and new photogrammetric maps with contour lines with an equidistance of 1 m were drawn for a 6–8 km broad coastal zone. The tsunami modelling is based on the assumption that the height of a future tsunami wave would be comparable with the one that reached the coastal area of Kenya in December 2004. Based on the regional geology of the Indian Ocean, it appears that the epicentre for a possible future earthquake that could lead to a new tsunami would most likely be situated in the eastern part of the ocean. Furthermore, based on a seismological assessment it has been estimated that the largest tsunami that can be expected to reach eastern Africa would have a 50% larger amplitude than the 2004 tsunami.It was therefore decided to carry out the simulation modelling with a tsunami wave similar to that of the 2004 event, but with the wave reaching the coast at the highest astronomical tide (scenario 1) and a worst case with a 50% larger amplitude (scenario 2: Fig. 3). The 2004 tsunami documented that the coastal belt of mangrove swamps provided some protection to the coastline by reducing the energy of the tsunami. Hence we included in this study a scenario 3 (Fig. 4), in which the mangrove areas along the coastline were removed. Maps for the three scenarios have been produced and show the areas that would be flooded, the degree of flooding, and the distribution of buildings such as schools and hospitals in the flooded areas. In addition, the force and velocity of the wave were calculated (COWI 2006).

Sign in / Sign up

Export Citation Format

Share Document