New High-Resolution Modeling of the 2018 Palu Tsunami, Based on Supershear Earthquake Mechanisms and Mapped Coastal Landslides, Supports a Dual Source

The Mw 7.5 earthquake that struck Central Sulawesi, Indonesia, on September 28, 2018, was rapidly followed by coastal landslides and destructive tsunami waves within Palu Bay. Here, we present new tsunami modeling that supports a dual source mechanism from the supershear strike-slip earthquake and coastal landslides. Up until now the tsunami mechanism: earthquake, coastal landslides, or a combination of both, has remained controversial, because published research has been inconclusive; with some studies explaining most observations from the earthquake and others the landslides. Major challenges are the numerous different earthquake source models used in tsunami modeling, and that landslide mechanisms have been hypothetical. Here, we simulate tsunami generation using three published earthquake models, alone and in combination with seven coastal landslides identified in earlier work and confirmed by field and bathymetric evidence which, from video evidence, produced significant waves. To generate and propagate the tsunamis, we use a combination of two wave models, the 3D non-hydrostatic model NHWAVE and the 2D Boussinesq model FUNWAVE-TVD. Both models are nonlinear and address the physics of wave frequency dispersion critical in modeling tsunamis from landslides, which here, in NHWAVE are modeled as granular material. Our combined, earthquake and coastal landslide, simulations recreate all observed tsunami runups, except those in the southeast of Palu Bay where they were most elevated (10.5 m), as well as observations made in video recordings and at the Pantoloan Port tide gauge located within Palu Bay. With regard to the timing of tsunami impact on the coast, results from the dual landslide/earthquake sources, particularly those using the supershear earthquake models are in good agreement with reconstructed time series at most locations. Our new work shows that an additional tsunami mechanism is also necessary to explain the elevated tsunami observations in the southeast of Palu Bay. Using partial information from bathymetric surveys in this area we show that an additional, submarine landslide here, when simulated with the other coastal slides, and the supershear earthquake mechanism better explains the observations. This supports the need for future marine geology work in this area.

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TSUNAMI PHASE SPEED REDUCTION DUE TO WATER COMPRESSIBILTY

Coastal Engineering Proceedings ◽

10.9753/icce.v36.currents.9 ◽

2018 ◽

pp. 9

Author(s):

Ali Abdolali ◽

James T. Kirby

Keyword(s):

Arrival Time ◽

Phase Speed ◽

Propagation Speed ◽

Frequency Dispersion ◽

Wave Theory ◽

Polar Coordinates ◽

Ocean Bottom ◽

Tsunami Propagation ◽

Boussinesq Model ◽

Tsunami Waves

Most existing tsunami propagation models consider the ocean to be an incompressible, homogenous medium. Recently, it has been shown that a number of physical features can slow the propagation speed of tsunami waves, including wave frequency dispersion, ocean bottom elasticity, water compressibility and thermal or salinity stratification. These physical effects are secondary to the leading order, shallow water or long wave behavior, but still play a quantifiable role in tsunami arrival time, especially at far distant locations. In this work, we have performed analytical and numerical investigations and have shown that consideration of those effects can actually improve the prediction of arrival time at distant stations, compared to incompressible forms of wave equations. We derive a modified Mild Slope Equation for Weakly Compressible fluid following the method proposed by Sammarco et al. (2013) and Abdolali et al. (2015) using linearized wave theory, and then describe comparable extensions to the Boussinesq model of Kirby et al. (2013). Both models account for water compressibility and compression of static water column to simulate tsunami waves. The mild slope model is formulated in plane Cartesian coordinates and is thus limited to medium propagation distances, while the Boussinesq model is formulated in spherical polar coordinates and is suitable for ocean scale simulations.

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Bulgarian tsunami on 7 May 2007: numerical investigation of the hypothesis of a submarine-landslide origin

Geological Society London Special Publications ◽

10.1144/sp477.6 ◽

2018 ◽

Vol 477 (1) ◽

pp. 303-313 ◽

Cited By ~ 2

Author(s):

Oleg I. Gusev ◽

Gayaz S. Khakimzyanov ◽

Leonid B. Chubarov

Keyword(s):

Black Sea ◽

Water Resistance ◽

Tsunami Wave ◽

Deformable Body ◽

Frequency Dispersion ◽

Submarine Landslide ◽

Generation Process ◽

Tsunami Waves ◽

Dispersion Effects ◽

Dispersive Model

AbstractWe investigate the ability of a submarine landslide to generate the tsunami waves observed on the Bulgarian coast of Black Sea on 7 May 2007. In our simulations, a landslide is presented as a quasi-deformable body moving along a curvilinear slope under action of the forces of gravity, buoyancy, water resistance and bottom friction. We employ the fully non-linear weakly dispersive model for tsunami wave simulations. The computations show that the initial landslide position on the real slope is extremely important for its dynamics and the wave generation process. We constructed some model landslides which generated similar waves to those observed. Moreover, these landslides stopped in the same region. Finally, we evaluated the significance of the frequency dispersion effects in the simulations.

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Multi-method observation and analysis of an impulse wave and tsunami caused by glacier calving

The Cryosphere Discussions ◽

10.5194/tcd-9-6471-2015 ◽

2015 ◽

Vol 9 (6) ◽

pp. 6471-6493 ◽

Cited By ~ 5

Author(s):

M. P. Lüthi ◽

A. Vieli

Keyword(s):

Tsunami Wave ◽

Tide Gauge ◽

Impulse Wave ◽

West Greenland ◽

Tsunami Waves ◽

The Future ◽

History Of ◽

Impulse Waves ◽

Run Up

Abstract. Glacier calving can cause violent impulse waves which, upon landfall, can lead to destructive tsunami-like waves. Here we present data acquired during a calving event from Eqip Sermia, an ocean-terminating glacier in West Greenland. During an exceptionally well documented event, the collapse of 9 × 105 m3 ice from a 200 m high ice cliff caused an impulse wave of 50 m height, traveling at a speed of 25–30 m s-1. This wave was filmed from a tour boat in 800 m distance from the calving face, and simultaneously measured with a terrestrial radar interferometer and a tide gauge. Tsunami wave run-up height on the steep opposite shore in 4 km distance was 10–15 m, destroying infrastructure and eroding old vegetation. These observations indicate that such high tsunami waves are a recent phenomenon in the history of this glacier. Analysis of the data shows that only moderately bigger tsunami waves are to be expected in the future, even under rather extreme scenarios.

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Near-coast tsunami waveguiding: phenomenon and simulations

Natural Hazards and Earth System Science ◽

10.5194/nhess-8-175-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 175-185 ◽

Cited By ~ 6

Author(s):

E. van Groesen ◽

D. Adytia ◽

Keyword(s):

Shallow Water ◽

High Variability ◽

Boussinesq Model ◽

Tsunami Waves ◽

Wave Amplification ◽

Reality Show ◽

Sloping Bottom

Abstract. In this paper we show that shallow, elongated parts in a sloping bottom toward the coast will act as a waveguide and lead to large enhanced wave amplification for tsunami waves. Since this is even the case for narrow shallow regions, near-coast tsunami waveguiding may contribute to an explanation that tsunami heights and coastal effects as observed in reality show such high variability along the coastline. For accurate simulations, the complicated flow near the waveguide has to be resolved accurately, and grids that are too coarse will greatly underestimate the effects. We will present some results of extensive simulations using shallow water and a linear dispersive Variational Boussinesq model.

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Analisis Pemodelan Tinggi dan Waktu Tempuh Gelombang Tsunami di Pesisir Pantai Bengkulu dengan Menggunakan Data Historis Gempa Bengkulu 12 september 2007

Prosiding SNFA (Seminar Nasional Fisika dan Aplikasinya) ◽

10.20961/prosidingsnfa.v1i0.4506 ◽

2017 ◽

Vol 1 ◽

pp. 52

Author(s):

Dwi Pujiastuti ◽

Rahmad Aperus ◽

Rachmad Billyanto

Keyword(s):

Travel Time ◽

Historical Data ◽

Tide Gauge ◽

Disaster Mitigation ◽

Tsunami Modeling ◽

Tsunami Modelling ◽

Tsunami Disaster ◽

Run Up ◽

Tsunami Run Up ◽

Coast Region

Abstract Tsunami modeling research has been done on the coast of Bengkulu using software L-2008 and Travel Time Tsunami (TTT). Earthquake historical data that used in this research is the earthquake in Bengkulu on September 12, 2007 which is obtained from BMKG and the USGS. This research is aimed to determine the height (run up) and travel time of the tsunami on the coast of Bengkulu as the tsunami disaster mitigation efforts. Tsunami modelling has been done by validate the run up using tide gauge data in the area of Padang, Muko-Muko, and Kaur. In this research used magnitude scenario are 8 Mw, 8.5 Mw and 9 Mw. Local tsunami effect observed were 10 areas along the coast region Bengkulu. Tsunami modeling of Bengkulu in September 12, 2007 results the run up value which is close to the run up value of the measurements. From the modelling result obtained that the quickest area impacted by the tsunami is Enggano Island which is 27 minutes 46 seconds from earthquake. The highest tsunami run up value is located in the Bengkulu city. The run up values by using the scenario of magnitude 8Mw is 2.07 m, 8.5 Mw is 4.05 m and 9 Mw is 9.83 m. Keywords: tsunami, modelling, software L-2008, software TTT, run up Abstrak Telah dilakukan penelitian pemodelan tsunami di pesisir Pantai Bengkulu dengan menggunakan software L-2008 dan Travel Time Tsunami (TTT). Data historis gempa bumi yang digunakan dalam penelitian ini adalah gempa bumi Bengkulu 12 September 2007 yang diperoleh dari BMKG dan USGS. Penelitian ini bertujuan untuk menentukan tinggi (run up) dan waktu tempuh gelombang tsunami di pesisir Pantai Bengkulu sebagai upaya mitigasi bencana tsunami. Sebagai validasi digunakan data run up stasiun tide gauge yang berlokasi di Padang, Muko-muko dan Kaur. Dalam penelitian ini dilakukan pemodelan tsunami untuk mengestimasi tinggi run up dan waktu tempuh penjalaran gelombang tsunami menggunakan skenario magnitudo 8 Mw, 8,5 Mw dan 9 Mw. Sebagai titik tinjau digunakan 10 daerah di sepanjang pantai wilayah Bengkulu. Hasil pemodelan menunjukkan bahwa nilai run up tsunami yang diperoleh mendekati nilai run up hasil pengukuran. Daerah dengan waktu tercepat dihantam gelombang tsunami adalah Pulau Enggano dengan waktu tempuh 27 menit dan 46 detik. Run up tertinggi terjadi di Kota Bengkulu. dengan nilai run up yang diperoleh adalah 2,07 m untuk skenario 8 Mw, 4,05 untuk skenario 8,5 Mw dan9,83 m untuk skenario 9 Mw. Kata kunci: :tsunami, pemodelan, software L-2008, software TTT, run up

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The Vertical Coseismic Deformation Field of the Samos-Izmir Earthquake (Mw6.9)

10.5194/egusphere-egu21-4767 ◽

2021 ◽

Author(s):

Muharrem Hilmi Erkoç ◽

Seda Özarpacı ◽

Alpay Özdemir ◽

Figen Eskiköy ◽

Efe Turan Ayruk ◽

...

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Source Region ◽

Coseismic Deformation ◽

Sea Level Changes ◽

Relative Sea Level ◽

Western Turkey ◽

Tsunami Waves ◽

Eastern Aegean ◽

Wave Heights

The Samos-Izmir Earthquake (Mw=6.9) of October 30, 2020 is among the strongest earthquakes that occurred in recent years throughout the Eastern Aegean. The epicenter of this earthquake was 14 km away from Samos Island and 25 km away from G&#252;m&#252;ld&#252;r-&#304;zmir region. The local tsunami with the wave heights reaching ~2m was triggered by the mainshock. The most affected areas were Sigacik and Akarca in Tukey (Yalciner et. al.,2020) and Vathy Town (NE Samos Island) in Greece (Triantafyllou et. al.,2020).In this study, we present an estimation of co-seismic deformations using an indirect approach based on GNSS, InSAR and Tide Gauge data. GNSS time series were used from 25 continuous GNSS stations data obtained from TUSAGA-Aktif in Turkey and NOANET in Greek, and the campaign GNSS measurement for 10 GNSS sites located at the western Turkey coast has been carried out after the earthquake. Moreover, InSAR deformation analyses have been performed using Sentinel-1 data. In addition, relative sea level changes have been analyzed in KOS, PLOMARI, and MENTES tide gauge stations.The vertical components of GPS stations have shown 10 cm uplift in Samos Island and 10 cm subsidence in the coast of Turkey. The results of the geodetic (GNSS, InSAR) analysis are consistent with each other. The rise time estimated here may correspond to the time elapsed shortly before the generation of tsunami waves reached up to 6 meters that propagated rapidly and caused significant damage around the source region. Also, it has been seen that whereas relative sea level in KOS and PLOMARI tide gauge stations are affected by the local tsunami, but relative sea level changes could not be observed in the MENTES station.

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Characteristics of Leading Tsunami Waves Generated in Three Recent Tsunami Events

Journal of Earthquake and Tsunami ◽

10.1142/s1793431114400016 ◽

2014 ◽

Vol 08 (03) ◽

pp. 1440001 ◽

Cited By ~ 15

Author(s):

Chao An ◽

Philip L.-F. Liu

Keyword(s):

Water Depth ◽

Wave Amplitude ◽

Propagation Speed ◽

Frequency Dispersion ◽

Wave Period ◽

Wave Crest ◽

Haida Gwaii ◽

Tsunami Waves ◽

Wave Nonlinearity ◽

Chile Tsunami

In this paper, the time series of ocean water surface elevation, recorded by Deep-ocean Assessment and Recording of Tsunamis (DART) sensors in the Pacific Ocean, during three recent tsunami events — 2010 Chile tsunami, 2011 Tohoku tsunami, and 2012 Haida Gwaii tsunami — are analyzed. The characteristics of leading tsunami waves are examined in terms of their propagation speed, wave period and wave amplitude so as to determine the importance of wave nonlinearity and frequency dispersion. Using the estimated arrival time of leading waves at each DART station and the distance from each station to the epicenter of the corresponding earthquake, the averaged propagation speed of leading waves for each event is calculated. It is found that the wave propagation speed for 2010 Chile tsunami is roughly 190 m/s, and is slightly slower than that of 2011 Tohoku and 2012 Haida Gwaii tsunamis, 210 m/s for both events. Two time scales associated with the leading waves are introduced: the duration of leading wave crest and the leading wave period obtained from a wavelet analysis. The results show that the leading wave crest duration is roughly 15–20 min and the wave period is roughly 25–30 min at most of DART stations for all the three events. The wave nonlinearity and frequency dispersion parameters, being defined as the wave amplitude to water depth ratio and the square of water depth to wavelength ratio, respectively, are calculated for the leading waves. The parameter for wave nonlinearity is found to be smaller than 4.0 × 10-4, while the parameter for frequency dispersion is smaller than 0.02 at all stations for all the three events. Finally, the cumulative effects of nonlinearity and frequency dispersion for the leading waves are investigated. It is found that the distances between the epicenter and all DART stations in each event are much smaller than those required for the nonlinearity and/or frequency dispersive effects to become significant.

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A dual-source nonlinear measurement system oriented to the empirical characterization of low-frequency dispersion in microwave electron devices

Computer Standards & Interfaces ◽

10.1016/j.csi.2010.06.008 ◽

2011 ◽

Vol 33 (2) ◽

pp. 165-175 ◽

Cited By ~ 1

Author(s):

Antonio Raffo ◽

Valeria Vadalà ◽

Pier Andrea Traverso ◽

Alberto Santarelli ◽

Giorgio Vannini ◽

...

Keyword(s):

Measurement System ◽

Low Frequency ◽

Frequency Dispersion ◽

Dual Source ◽

Electron Devices

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Structure and performance of a real-time algorithm to detect tsunami or tsunami-like alert conditions based on sea-level records analysis

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-1499-2011 ◽

2011 ◽

Vol 11 (5) ◽

pp. 1499-1521 ◽

Cited By ~ 15

Author(s):

L. Bressan ◽

S. Tinti

Keyword(s):

Real Time ◽

Sea Level ◽

Tide Gauge ◽

Sampling Rate ◽

High Amplitude ◽

Time Algorithm ◽

Detection Algorithm ◽

Detection Methods ◽

Tsunami Waves ◽

Single Station

Abstract. The goal of this paper is to present an original real-time algorithm devised for detection of tsunami or tsunami-like waves we call TEDA (Tsunami Early Detection Algorithm), and to introduce a methodology to evaluate its performance. TEDA works on the sea level records of a single station and implements two distinct modules running concurrently: one to assess the presence of tsunami waves ("tsunami detection") and the other to identify high-amplitude long waves ("secure detection"). Both detection methods are based on continuously updated time functions depending on a number of parameters that can be varied according to the application. In order to select the most adequate parameter setting for a given station, a methodology to evaluate TEDA performance has been devised, that is based on a number of indicators and that is simple to use. In this paper an example of TEDA application is given by using data from a tide gauge located at the Adak Island in Alaska, USA, that resulted in being quite suitable since it recorded several tsunamis in the last years using the sampling rate of 1 min.

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Active tectonics along the submarine slope of south-eastern Sicily and the source of the 11 January 1693 earthquake and tsunami

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-1311-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 1311-1319 ◽

Cited By ~ 34

Author(s):

A. Argnani ◽

A. Armigliato ◽

G. Pagnoni ◽

F. Zaniboni ◽

S. Tinti ◽

...

Keyword(s):

Tide Gauge ◽

Active Tectonics ◽

Historical Earthquakes ◽

Fault System ◽

Tide Gauge Records ◽

Submarine Slide ◽

Tsunami Waves ◽

South Eastern ◽

Run Up ◽

Historical Accounts

Abstract. South-eastern Sicily has been affected by large historical earthquakes, including the 11 January 1693 earthquake, considered the largest magnitude earthquake in the history of Italy (Mw = 7.4). This earthquake was accompanied by a large tsunami (tsunami magnitude 2.3 in the Murty-Loomis scale adopted in the Italian tsunami catalogue by Tinti et al., 2004), suggesting a source in the near offshore. The fault system of the eastern Sicily slope is characterised by NNW–SSE-trending east-dipping extensional faults active in the Quaternary. The geometry of a fault that appears currently active has been derived from the interpretation of seismic data, and has been used for modelling the tsunamigenic source. Synthetic tide-gauge records from modelling this fault source indicate that the first tsunami wave polarity is negative (sea retreat) in almost all the coastal nodes of eastern Sicily, in agreement with historical observations. The outcomes of the numerical simulations also indicate that the coastal stretch running from Catania to Siracusa suffered the strongest tsunami impact, and that the highest tsunami waves occurred in Augusta, aslo in agreement with the historical accounts. A large-size submarine slide (almost 5 km3) has also been identified along the slope, affecting the footwall of the active fault. Modelling indicates that this slide gives non-negligible tsunami signals along the coast; though not enough to match the historical observations for the 1693 tsunami event. The earthquake alone or a combination of earthquake faulting and slide can possibly account for the large run up waves reported for the 11 January 1693 event.

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