Lessons learnt from Simulations and Observations of 28 September 2018 Palu tsunami
Authors
Sunanda Manneela, Ch Patanjali Kumar, B. Ajay Kumar, PLN Murthy, E. Pattabhi Rama Rao, SSC Shenoi
Source
8th Tsunami and Safety Symposium www.isope.org
Abstract
Indonesia has a long history of great earthquakes that cause structural damages andor tsunami. On 28 September 2018, astrike-slip earthquake with moment magnitude Mw 7.5 occurred on the Sulawesi Island, generating unexpected tsunami leading to unprecedented disaster ~2,500 victims in coastal areas of Palu and Donggala. Here tsunami characteristics are analyzed through combination of preliminary field data and numerical modeling. Despite the IOWave18 tsunami exercise mock drill conducted in the same month, many people were trapped in tsunami.
To understand the observed tsunami hydrodynamics at regional and local scales, numerical simulations of tsunami were performed using AD-CIRC model. The good agreement in the time-series is confirmed with run-up heights. Though the earthquake magnitude considered moderate, run-up values are large. In addition, tsunami occurred on closed coast that stretches about50 km with morphological structures that could funnel tsunami energy from Donggala to Palu. Though it is obvious that the large seismic moment Mo of shallow underwater or coastal earthquakes ispassable to generate large run-up heights, local tsunami severity depends on tsunami wave energy that mounds on local bathymetric propagation paths and other submarine site specific effect. One of themajor challenges even today in the tsunami science is to rapidly assess a local tsunami severity frompreliminary earthquake parameters. Here we assess the tsunami generation and propagation modeling scenarios to improve our understanding of local tsunami behaviournear the genesis region.Understanding these processes is relevant for the regions, which still possess a significant tsunamigenic potential.
Paper No
2
Publication ID : 752 & Year : 2015
Title
The admissible tsunamigenic source region of 24 September 2013 land-based earthquake application of backward ray tracing technique
Authors
Patanjali Kumar, Ch and Ajaya Kumar, B and Devi, EU and Mahendra, RS and Sunanda, MV and Pradeep Kumar, M and Padmanabham, J and Dipankar, S and Srinivasa Kumar, T
Source
Current Science, 108 (9), 2015. pp. 1712-1716. www.currentscience.ac.in/Volumes/108/09/1712.pdf
Abstract
A minor tsunami of about 50 cm was generated along the coast of Qurayat near Makran subduction zone in the Arabian Sea due to the 24 September 2013 Pakistan earthquake of magnitude 7.6 Mw(mB),although its source was ~200 km far inland of the Makran trench. The real time sea level observation network in the Arabian Sea recorded minor tsunami arrivals. In an attempt to explain the mechanism of this unusual tsunami, we use backward ray tracing technique to map the admissible region of tsunamigenic source. Basically, in this technique the ray equations are integrated starting from the specific locations of tsunami observations, in all possible directions. The known travel time of the initial waves to the respective tide gauges and tsunami buoys is used in this method. Backward wave front is constructed by joining all endpoints of the rays from each of the locations. The region where the envelope of all backward wave fronts converges is considered as the source of the tsunami, which is ~470 km from the earthquake epicentre with the location at 24.8 N and 61.5E. The admissible region identified is an undersea section between Chabahar and Gwadar, where a mud island had appeared subsequent to this earthquake. Convergence of the tsunami source zone and location of the mud island suggest that the sudden uplift must have caused the tsunami
Paper No
3
Publication ID : 756 & Year : 2014
Title
The tsunami impact on Indian ocean coasts by the strike-slip earthquakes
(POSTER)
Authors
Ch.Patanjali Kumar, P. Lakshmi Narashima Murty, B. Ajay Kumar, J. Padmanabham, E. Uma Devi, M.V. Sunanda, P. Sai Bharadwaj, R.S. Mahendra and T. Srinivas Kumar
Source
International Symposium on the Indian Ocean Dynamic of Indain Ocean: Perspective and Reterospective, Nov30, 2014
Abstract
The Indian Tsunami Early Warning Centre (ITEWC) in Hyderabad monitored the 11 April 2012 tsunami off the coast of Sumatra, which was generated by a shallow strike⿿slip earthquake and it largest aftershock of magnitude Mw (mB) 8.5 and 8.2 respectively, that occurred inside the subducting slab of the Indian plate. The earthquake occurred at 08:38 UTC and triggered a small ocean-wide tsunami that has been recorded by various tide gauges and tsunami buoys located in the Indian Ocean region. The expected wave amplitudes and inundation extents at coast due this event were modeled using the shallow water wave inundation model TUNAMI N2. The first tsunami wave with an amplitude of 0.3 m observed at Campbell-Bay at 0942 UTC, whereas the first wave of 0.12 m amplitude was observed at Nancowry tide gauges at 1000 UTC. The maximum wave amplitude observed at Ennore, Chennai and Visakhapatnam Tide gauge stations was only 0.1 m. The modeled wave amplitudes were fairly matched with these observations. Inundation extents were also modeled for this event using publicly available data sources such as topography and bathymetry. It was noticed that there was not any problem in used seismic source parameters and open ocean bathymetry as the modeled wave amplitudes were in good agreement with observed records. Whereas the accuracy in modeled inundation extent is depends on the near shore topography and bathymetry.
Paper No
4
Publication ID : 498 & Year : 2013
Title
An assessment of the diversity in scenario-based tsunami forecasts for the Indian Ocean
Authors
Greenslade, D.J.M., Annunziato, A., Babeyko, A.Y., Burbidge, D.R., Ellguth, E., Horspool, N., Srinivasa Kumar, T., Kumar, Ch.Patanjali., Moore, C.W., Rakowsky, N., Riedlinger, T., Ruangrassamee, A., Srivihok, P., Titov, V.V.
Source
Continental Shelf Research (URL:
http://dx.doi.org/10.1016/j.csr.2013.06.001)
Abstract
This work examines the extent to which tsunami forecasts from different numerical forecast systems might be expected to differ under real-time conditions. This is done through comparing tsunami amplitudes from a number of existing tsunami scenario databases for eight different hypothetical tsunami events within the Indian Ocean. Forecasts of maximum tsunami amplitude are examined at 10 output points distributed throughout the Indian Ocean at a range of depths. The results show that there is considerable variability in the forecasts and on average, the standard deviation of the maximum amplitudes is approximately 62% of the mean value. It is also shown that a significant portion of this diversity can be attributed to the different lengths of the scenario time series. These results have implications for the interoperability of Regional Tsunami Service Providers in the Indian Ocean.
Paper No
5
Publication ID : 760 & Year : 2013
Title
Site Response Studies Based on Ambient Noise Measurements in Bangalore
Authors
Srinagesh, D & Chadha, R.K. & V. Ramana, D & S. P. Sarma, C & Sekhar, M & Ch, Patanjali
Source
Interline Publishing, Bangalore (2013). Available online (URL: https://www.researchgate.net/publication/242364210_Site_Response_Studies_Based_on_Ambient_Noise_Measurements_in_Bangalore)
Abstract
In assessing the seismic Hazard of any urban center, ambient noise measurements have been quite a popular method in estimating the amplification and the dominant frequencies for the horizontal motion during earthquakes. The procedure has several advantages and one of them significantly is that a seismic station with three components is needed and is not necessary to wait for a longer time to record earthquakes. In estimating the site response Nakamura technique has been widely used and the resonance frequency is obtained by evaluating the horizontal to vertical spectral ratio (Nakamura, 1989). The main consideration of this technique is the micro tremors are primarily composed of Rayleigh waves, produced by local sources. These waves propagate in a surface layer over a half space, considering the motion at the interface of the surface layer and half space is not affected by the source effect and that the horizontal and verticalmotion at this interface is approximately equal. The site response studies to be undertaken in Bangalore was decided in the first meeting of the Expert Group on Microzonation of Bangalore Urban Centre which was held on 29th April 2005, at IISC Bangalore. The objective for undertaking the microzonation of Bangalore Metropolis is that it has attained the status of the fastest growing city in India. It is also a city where a number of high profile institutes and Laboratories are located, a major hub for space and aeronautics, together with the largest concentration of IT industry. Further, southern part of Karnataka is prone for moderate seismic activity which is evident from Figure 1 and 2. In view of the above perspective a microzonation project was embarked upon by IISC Bangalore, NGRI Hyderabad, GSI Bangalore circle, CMMACS, IMD and various other organizations.
Paper No
6
Publication ID : 757 & Year : 2012
Title
Successful monitoring of April 11, 2012 off coast of Sumatra tsunami by Indian Tsunami Early Warning Center (ITEWC)
Authors
T. Srinivasa Kumar, Shailesh Nayak, Ch. Patanjali Kumar, R. B. S. Yadav, B. Ajay Kumar, M. V. Sunanda, E. Uma Devi, N. Kiran Kumar, S. A. Kishore and S. S. C. Shenoi
Source
Current Science, Vol. 102, No. 11, 10 June 2012
Abstract
The Indian Tsunami Early Warning Centre (ITEWC) in Hyderabad monitored the 11 April 2012 tsunami off the coast of Sumatra,which was generated by a shallow strike⿿slip earthquake and it largest aftershock of magnitude Mw(mB) 8.5 and 8.2 respectively, that occurred inside the subducting slab of the Indian plate. The earthquake generated a small ocean-wide tsunami that has been recorded by various tide gauges and tsunami buoys located in the Indian Ocean region. ITEWC detected the earthquake within 3 min 52 s and issued six advisories (bulletins) according to its Standard Operating Procedure. The ITEWC performed well during the event, and avoided false alarms and unnecessary public evacuations, especially in the mainland part of India region.
Paper No
7
Publication ID : 755 & Year : 2010
Title
Performance of the Indian Tsunami Early Warning System
Authors
T. Srinivasa Kumar, Ch. Patanjali Kumar and Shailesh Nayak
Source
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Science, Volume XXXVIII, Part 8, Kyoto Japan 2010, 271-274
Abstract
The Indian Tsunami Early Warning System (ITEWS) based at Indian National Center for Ocean
Information Services (INCOIS), Hyderabad is responsible for issuing tsunami advisories to authorized officials from the Ministry of Home Affairs (MHA) and Ministry of Earth Sciences (MoES) in India. The centre operates on 24x7 basis and has the functions of monitoring seismological stations, bottom pressure recorders (BPRs) and tidal stations throughout the Indian Ocean Basin to evaluate potentially tsunamigenic earthquakes and disseminating tsunami warning information. A database of all possible earthquake scenarios for the Indian Ocean is
used to identify the regions under risk at the time of event. Timely tsunami advisories (Warning/Alert/Watch/Information) are generated following pre-set decision support rules and standard operating procedure (SOP). The end-to-end system performance was very well tested for the first time after its establishment against the earthquake and tsunami event on September 12, 2007 Off the west coast of Sumatra. The Indian system equipped with world-class computational, communication and technical support facility is capable of detecting tsunamis in the Indian Ocean. With this capability INCOIS has begun providing regional tsunami watch services on a trial basis from its national system for the Indian Ocean region.
Paper No
8
Publication ID : 754 & Year : 2009
Title
Geo spatial Technology Solution for Indian National Tsunami Early Warning System
Authors
T. Srinivasa Kumar, Ch. Patanjali Kumar, B. Ajay Kumar, Shailesh Nayak, Srinivasu Mulukutla and Vittal T. S.,
Source
Map world forum 2009February 28, 2009, (Available online at URL: http://gisdevelopment.net/proceedings/mapworldforum/2009/index.htm)
Abstract
Tsunami is a system of ocean gravity waves formed as a result of large scale disturbance of the sea floor that occurs in a relatively short duration of time. The Indian Ocean is likely to be affected by tsunamis generated mainly by earthquakes from the two potential source regions,the AndamanNicobar Sumatr a Island Arc and the Makran Subduction Zone. A state of the art warning centre has been established at INCOIS with all the necessary computational and communication infrastructure that enables reception of real time data from the network of national and international seismic stations, tide gauges and bottom pressure recorders (BPRs) .Earthquake parameters are computed in the less than 15 minutes of occurrence. A database of pre r un scenarios for travel times and runup height has been created using Tunami N2 model. At the time of event, the closest scenario is picked from the database for generating advisories. Water level data enables confirmation or cancellation of a tsunami. Tsunami bulletins are then generated based on decision support rules and disseminated to the concerned authorities for action, following a standard operating procedur e. One of the key components of the early warning centre is the development of application software around GIS technology that per forms end to end 24 X 7 operations right from data reception, display,analysis, modelling, and decision support system for generation of tsunami advisories following a standard operating procedure
Paper No
9
Publication ID : 753 & Year : 2009
Title
Decision support system and Standard Operating Procedure for Tsunami Early Warning Centre
Authors
Patanjali Kumar, Ch., Raghavendra S. M., Mahendra, R. S., Ajay Kumar, B., Mohanty, P. C., Srinivasa Kumar, T. and Nayak, S
Source
Joint International Workshop of ISPRS WG IV/1,WG VIII/1 and WG IV/3 on 'Geospatial Data Infrastructure and Real-time Services with special emphasis on Disaster Management', November 25-27, 2009, Hyderabad, India
Abstract
Aftermath Dec26, 2004 ⿿ the Boxing Day tsunami, the Indian government had formulated tsunami warning system for Indian Ocean to monitor and forecast tsunamis. The Indian tsunami early warning centre at Indian National Centre for Ocean Information Services (INCOIS), Hyderabad is made operational for 24 X 7 basis from 15 October 2007. The Decision Support System (DSS) at early warning centre is intended to Monitor the online input data from individual sensors, Generate automatic alarms based on preset decision rules for one or many of the input parameters and Carry out criteria-based analysis for one or many of the above mentioned input parameters to generate online advisories. The criteria for generation of different types of advisories (warning/alert/watch) for a particular region of the coast are to be based on the available warning time (i.e. time taken by the tsunami wave to reach the particular coast). The warning criteria are based on the premise that coastal areas falling within 60 minutes travel time from a tsunamigenic earthquake source need to be warned based solely on earthquake information, since enough time will not be available for confirmation of water levels from BPRs and tide gauges. Those coastal areas falling outside the 60 minutes travel time from a tsunamigenic earthquake source could be put under a watch status and upgraded to a warning only upon confirmation of water-level data.
Paper No
10
Publication ID : 758 & Year : 2007
Title
Attenuation studies based on local earthquake Coda waves in the southern Indian peninsular shield
Authors
Ch Patanjali Kumar, Sarma, C.S.P, Shekar, M and Chadha, R.K
Source
Natural Hazards, 2007, Volume 40, Number 3, Pages 527-536
Abstract
The Dharwar craton, Cuddapah basin and the Godavari graben characterise three diverse geological and tectonic settings in the peninsular shield of India. Owing to their contiguous proximity, they offer a unique opportunity to document differences, if any, in their seismic wave attenuation characteristics that might have a bearing on the seismogenic nature of the crust in a craton, basin and a rift-like graben structure. An attempt is made here to bring out these differences using constraints from coda-Q. We considered local earthquakes with epicentral distances ranging from␣14 to 150 km recorded at the digital broadband stations at Dharwar (DHD), Cuddapah (CUD) and Kothagudem (KGD) regions to derive the frequency-dependent coda-Q relations. Using the single scattering method, we obtained the frequency-dependent Q C relationship (Q C = Q 0 f n )for each of the three geological units separately: DHD: Q C = (730.62 ± 0.09)f (0.54 ± 0.01); CUD: Q C = (535.06 ± 0.13)f (0.59 ± 0.01) and KGD: Q C = (150.56 ± 0.08)f⿿ (0.91 ± 0.01). The Q C values obtained for all the three sub-regions show moderate to strong frequency dependence and essentially reflect the level of crustal heterogeneities to varying degrees.
Paper No
11
Publication ID : 761 & Year : 2006
Title
Estimation of source parameters for 14March 2005 earthquake of Koyna-Warna region
Authors
B, Ajay & V. Ramana, D & Ch, Patanjali & Rani, V & Shekar, Mandadi & Srinagesh, D & Chadha, R.K
Source
Current science (2006). 24. 526-530
Abstract
The source parameters for the 14 March 2005 earthquake in the Koyna⿿Warna region have been estimated using data from three broadband seismological observato-ries installed by us at regional distances in the Indian Peninsular shield. Spectral analysis of SH-waveform on transverse component of the three-component seismograms is performed. The estimated seismic moment (M0), source radius (r), stress drop (Ds) and moment magnitude (Mw ) for this earthquake are 3.9 ´ 10 16 N-m, 975 m, 19 MPa and 5.1 respectively. The near-surface attenuation factor (k) is found to be of the order of 0.01 for the stable shield region, suggesting a thin low-velocity sediment beneath the region. The estimated stress drop of the earthquake is higher compared to the other intraplate earthquakes in India. The focal mecha-nism solution estimated for this event using amplitudes and polarities of direct P-and S-waves suggests the fault plane with strike N312°, dip 36°and rake 248°.
