scholarly journals Probabilistic near‐field tsunami source and tsunami run‐up distribution inferred from tsunami run‐up records in northern Chile

Author(s):  
Jun‐Whan Lee ◽  
Jennifer L. Irish ◽  
Robert Weiss
2021 ◽  
Author(s):  
Jun-Whan Lee ◽  
Jennifer Irish ◽  
Robert Weiss

Understanding a tsunami source and its impact is vital to assess a tsunami hazard. Thanks to the efforts of the tsunami survey teams, high-quality tsunami run-up data exists for contemporary events. Still, it has not been widely used to infer a tsunami source and its impact mainly due to the computational burden of the tsunami forward model. In this study, we propose a TRRF-INV (Tsunami Run-up Response Function-based INVersion) model that can provide probabilistic estimates of a near-field tsunami source and tsunami run-up distribution from a small number of run-up records. We tested the TRRF-INV model with synthetic tsunami scenarios in northern Chile and applied it to the 2014 Iquique, Chile, tsunami event as a case study. The results demonstrated that the TRRF-INV model can provide a reasonable tsunami source estimate to first order and estimate tsunami run-up distribution well. Moreover, the case study results agree well with the United States Geological Survey report and the global Centroid Moment Tensor solution. We also analyzed the performance of the TRRF-INV model depending on the number and the uncertainty of run-up records. We believe that the TRRF-INV model has the potential for supporting accurate hazard assessment by (1) providing new insights from tsunami run-up records into the tsunami source and its impact, (2) using the TRRF-INV model as a tool to support existing tsunami inversion models, and (3) estimating a tsunami source and its impact for ancient events where no data other than estimated run-up from sediment deposit data exists.


Author(s):  
Juh-Whan Lee ◽  
Jennifer L. Irish ◽  
Robert Weiss

Since near-field-generated tsunamis can arrive within a few minutes to coastal communities and cause immense damage to life and property, tsunami forecasting systems should provide not only accurate but also rapid tsunami run-up estimates. For this reason, most of the tsunami forecasting systems rely on pre-computed databases, which can forecast tsunamis rapidly by selecting the most closely matched scenario from the databases. However, earthquakes not included in the database can occur, and the resulting error in the tsunami forecast may be large for these earthquakes. In this study, we present a new method that can forecast near-field tsunami run-up estimates for any combination of earthquake fault parameters on a real topography in near real-time, hereafter called the Tsunami Run-up Response Function (TRRF).Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/tw1D29dDxmY


Author(s):  
Debashis Basu ◽  
Robert Sewell ◽  
Kaushik Das ◽  
Ron Janetzke ◽  
Biswajit Dasgupta ◽  
...  

This paper presents computational results for predicting earthquake-generated tsunami from a developed integrated computational framework. The computational framework encompasses the entire spectrum of modeling the earthquake-generated tsunami source, open-sea wave propagation, and wave run-up including inundation and on-shore effects. The present work develops a simplified source model based on pertinent local geologic and tectonic processes, observed seismic data (i.e., data obtained by inversion of seismic waves from seismographic measurements), and geodetic data (i.e., directly measured seafloor and land deformations). These source models estimated configurations of seafloor deformation used as initial waveforms in tsunami simulations. Together with sufficiently accurate and resolved bathymetric and topographic data, they provided the inputs needed to numerically simulate tsunami wave propagation, inundation and coastal impact. The present work systematically analyzes the effect of the tsunami source model on predicted tsunami behavior and the associated variability for the 2011 Tōhuku-Oki tsunami. Simulations were carried out for the 2011 Tōhuku -Oki Tsunami that took place on March 11, 2011, from an MW 9.1 earthquake. The numerical simulations were performed using the fully nonlinear Boussinesq hydrodynamics code, FUNWAVE-TVD (distributed by the University of Delaware). In addition, a sensitivity analysis was also carried out to study the effect of earthquake magnitude on the predicted wave height. The effect of coastal structure on the wave amplification at the shore is also studied. Simulated tsunami results for wave heights are compared to the available observational data from GPS (Global Positioning System) at the central Miyagi location.


2021 ◽  
Author(s):  
Jun-Whan Lee ◽  
Jennifer Irish ◽  
Robert Weiss

Rapid prediction of the spatial distribution of the run-up from near- field tsunamis is critically important for tsunami hazard characterization. Even though significant advances have been made over the last decade, physics- based numerical models are still computationally intensive. Here, we present a response surface methodology (RSM)-based model called the tsunami run-up response function (TRRF). Derived from a discrete set of tsunami simulations, TRRF can produce a rapid prediction of a near-field tsunami run-up distribution that takes into account the influence of variable local topographic and bathymetric characteristics in a given region. This new method reduces the number of simulations required to build an RSM model by separately modeling the leading order contribution and the residual part of the tsunami run-up distribution. Using the northern region of Puerto Rico as a case study, we investigated the performance (accuracy, computational time) of the TRRF. The results reveal that the TRRF achieves reliable prediction while reducing the prediction time by six orders of magnitude (computational time: < 1 second per earthquake).


2011 ◽  
Vol 1 (32) ◽  
pp. 26 ◽  
Author(s):  
Torsten Schlurmann ◽  
Widjo Kongko ◽  
Nils Goseberg ◽  
Danny Hilman Natawidjaja ◽  
Kerry Sieh

Near-field tsunami propagation both in shallow water environments and bore-like wave propagation on land are conducted in this study to obtain fundamental knowledge on the tsunami hazard potential in the city of Padang, Western Sumatra, Republic of Indonesia. As the region proves a huge seismic moment deficit which has progressively accumulated since the last recorded major earthquakes in 1797 and 1833, this investigation focuses on most reasonable seismic sources and possibly triggered nearshore tsunamis in order to develop upgraded disaster mitigations programs in this densely-populated urban agglomeration located on the western shore of Sumatra Island. Observations from continuous Global Positioning Satellite (cGPS) systems and supplementary coral growth studies confirm a much greater probability of occurrence that a major earthquake and subsequent tsunami are likely to strike the region in the near future. Newly surveyed and processed sets of geodata have been collected and used to progress most plausible rupture scenarios to approximate the extent and magnitudes of a further earthquake. Based upon this novel understanding, the present analysis applies two hydronumerical codes to simulate most probable tsunami run-up and subsequent inundations in the city of Padang in very fine resolution. Run-up heights and flow-depths are determined stemming from these most plausible rupture scenarios. Evaluation of outcome and performance of both numerical tools regarding impacts of surge flow and bore-like wave fronts encountering the coast and inundating the city are thoroughly carried out. Results are discussed not only for further scientific purposes, i.e. benchmark tests, but also to disseminate main findings to responsible authorities in Padang with the objective to distribute the most probable dataset of plausible tsunami inundations as well as to address valuable insights and knowledge for effective counter measures, i.e. evacuation routes and shelter building. Following evacuation simulations based on rational assumptions and simplifications reveal a most alerting result as about 260.000 people are living in the highly exposed potential tsunami inundation area in the city of Padang of which more than 90.000 people will need more than 30 min. to evacuate to safe areas.


2021 ◽  
Vol 9 (1) ◽  
pp. 68
Author(s):  
Ioanna Triantafyllou ◽  
Marilia Gogou ◽  
Spyridon Mavroulis ◽  
Efthymios Lekkas ◽  
Gerassimos A. Papadopoulos ◽  
...  

The tsunami generated by the offshore Samos Island earthquake (Mw = 7.0, 30 October 2020) is the largest in the Aegean Sea since 1956 CE. Our study was based on field surveys, video records, eyewitness accounts and far-field mareograms. Sea recession was the leading motion in most sites implying wave generation from seismic dislocation. At an epicentral distance of ~12 km (site K4, north Samos), sea recession, followed by extreme wave height (h~3.35 m), occurred 2′ and 4′ after the earthquake, respectively. In K4, the main wave moved obliquely to the coast. These features may reflect coupling of the broadside tsunami with landslide generated tsunami at offshore K4. The generation of an on-shelf edge-wave might be an alternative. A few kilometers from K4, a wave height of ~1 m was measured in several sites, except Vathy bay (east, h = 2 m) and Karlovasi port (west, h = 1.80 m) where the wave amplified. In Vathy bay, two inundations arrived with a time difference of ~19′, the second being the strongest. In Karlovasi, one inundation occurred. In both towns and in western Turkey, material damage was caused in sites with h > 1 m. In other islands, h ≤ 1 m was reported. The h > 0.5 m values follow power-law decay away from the source. We calculated a tsunami magnitude of Mt~7.0, a tsunami source area of 1960 km2 and a displacement amplitude of ~1 m in the tsunami source. A co-seismic 15–25 cm coastal uplift of Samos decreased the tsunami run-up. The early warning message perhaps contributed to decrease the tsunami impact.


Author(s):  
Gentur Handoyo ◽  
Agus A.D. Suryo Putro ◽  
Petrus Subardjo

<p align="center"><strong><em>ABSTRACT</em></strong></p><p><em>The tsunami often hitthe southern coast of Java several times, where Parangtritis located in that area. This is due to the meeting of Indo-Australian plate with the Eurasian plate in the south of Java that results in a major tectonic tsunami source. Tsunami waves from this region takes 50 to 100 minutes to reach the beach. Considering the short span of time to self-rescue</em><em>,</em><em> than its necessary to concieve a map of vulnerability to the tsunami region to plan evacuation routes and </em><em>tsunami temporary </em><em>evacuation place (TES) tsunami incoastal village of Parangtritis. The material used as an object to study in this research is the vulnerability of the tsunami, tsunami runoff based on the runup height, the proposed evacuation routes and </em><em>tsunami temporary </em><em>evacuation place (TES) as. The result</em><em>,</em><em>village </em><em>in </em><em>Parangtritis</em><em> is a</em><em> tsunami prone areas with vast percentage of the tsunami-prone areas at 66.45%. When the </em><em>tsunami run up reach </em><em>16m the affected area </em><em>was </em><em>788.07 Ha. There are three proposed evacuation route through the Parangtritis</em><em> roads</em><em>, Depok roads and Depok-Parangtriti</em><em>s road</em><em>s. There are 12 proposed temporary evacuation place which spread in the village Parangtritis. </em><em></em></p><p><strong>Keywords</strong>:<em> </em><em>Inundation</em><em>, Plate, Runup</em><em></em></p>


2021 ◽  
Author(s):  
Ignatius Ryan Pranantyo ◽  
Athanasius Cipta ◽  
Hasbi Shiddiqi ◽  
Mohammad Heidarzadeh

&lt;p&gt;An M7.0 earthquake followed by moderate tsunami destructed Majene region, western Sulawesi on 23 February 1969. This event claimed at least 64 lives and caused severe damage to infrastructure. In this study, we reconstructed the earthquake and tsunami source of this event by optimising macroseismic and tsunami dataset reported as well as analysed the earthquake focal mechanism. We estimated that the maximum intensity of the earthquake was VIII (in Modified Mercalli Intensity). From the first motion polarity analysis, the earthquake had a thrust mechanism which was plausibly from the Makassar Thrust. Further, deterministic ground motion modelling successfully fits the intensity data. However, thrust earthquake from the Makassar Thrust was unable to reconstruct 4 m tsunami height observed at Pelattoang. The estimated ratio between maximum tsunami run-up height and lateral distribution distance (&lt;em&gt;I&lt;sub&gt;2&lt;/sub&gt;&lt;/em&gt;) from the dataset indicates that the tsunami was generated by a local coastal landslide.&lt;/p&gt;&lt;p&gt;(This study is funded by the Royal Society (UK) grant number CHL/R1/180173)&lt;/p&gt;


2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Tatsuo Ohmachi ◽  
Shusaku Inoue ◽  
Tetsuji Imai

The 2003 Tokachi-oki earthquake (MJ 8.0) occurred off the southeastern coast of Tokachi, Japan, and generated a large tsunami which arrived at Tokachi Harbor at 04:56 with a wave height of 4.3 m. Japan Marine Science and Technology Center (JAMSTEC) recovered records of water pressure and sea-bed acceleration at the bottom of the tsunami source region. These records are first introduced with some findings from Fourier analysis and band-pass filter analysis. Water pressure disturbance lasted for over 30 minutes and the duration was longer than those of accelerations. Predominant periods of the pressure looked like those excited by Rayleigh waves. Next, numerical simulation was conducted using the dynamic tsunami simulation technique able to represent generation and propagation of Rayleigh wave and tsunami, with a satisfactory result showing validity and usefulness of this technique. Keywords: Earthquake, Rayleigh wave, tsunami, near-field


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