scholarly journals Alternative Approach for Tsunami Early Warning Indicated by Gravity Wave Effects on Ionosphere

2021 ◽  
Vol 13 (11) ◽  
pp. 2150
Author(s):  
Zahra Foroodi ◽  
Mahdi Alizadeh ◽  
Harald Schuh ◽  
Lung-Chih Tsai
Keyword(s):  
Early Warning ◽  
Tohoku Earthquake ◽  
Volcanic Eruptions ◽  
The United States ◽  
Internal Gravity Waves ◽  
The 2011 Tohoku Earthquake ◽  
Maximum Increase ◽  
Ionospheric Layer ◽  
Tsunami Early Warning ◽  
Tsunami Waves

The rapid displacement of the ocean floor during large ocean earthquakes or volcanic eruptions causes the propagation of tsunami waves on the surface of the ocean, and consequently internal gravity waves (IGWs) in the atmosphere. IGWs pierce through the troposphere and into the ionospheric layer. In addition to transferring energy to the ionosphere, they cause significant variations in ionospheric parameters, so they have considerable effects on the propagation of radio waves through this dispersive medium. In this study, double-frequency measurements of the Global Positioning System (GPS) and ionosonde data were used to determine the ionospheric disturbances and irregularities in response to the tsunami induced by the 2011 Tohoku earthquake. The critical frequency of the F2 layer (foF2) data obtained from the ionosonde data also showed clear disturbances that were consistent with the GPS observations. IGWs and tsunami waves have similar propagation properties, and IGWs were detected about 25 min faster than tsunami waves in GPS ground stations at the United States west coast, located about 7900 km away from the tsunami’s epicenter. As IGWs have a high vertical propagation velocity, and propagate obliquely into the atmosphere, IGWs can also be used for tsunami early warning. To further investigate the spatial variation in ionospheric electron density (IED), ionospheric profiles from FORMOSAT-3/COSMIC (F3/C) satellites were investigated for both reference and observation periods. During the tsunami, the reduction in IED started from 200 km and continued up to 272 km altitude. The minimum observed reduction was 2.68 × 105 el/cm3, which has happened at 222 km altitude. The IED increased up to 767 km altitude continuously, such that the maximum increase was 3.77 × 105 el/cm3 at 355 km altitude.

scholarly journals Instant tsunami early warning based on real-time GPS – Tohoku 2011 case study

2013 ◽  
Vol 13 (5) ◽  
pp. 1285-1292 ◽  
Author(s):  
A. Hoechner ◽  
M. Ge ◽  
A. Y. Babeyko ◽  
S. V. Sobolev
Keyword(s):  
Real Time ◽  
Early Warning ◽  
Synthetic Data ◽  
Tohoku Earthquake ◽  
Tsunami Propagation ◽  
The 2011 Tohoku Earthquake ◽  
Tsunami Early Warning ◽  
Complete Processing ◽  
Gps Observations

Abstract. Taking the 2011 Tohoku earthquake as an example, we demonstrate the ability of real-time GPS to provide qualified tsunami early warning within minutes. While in earlier studies we demonstrated the power of the so-called GPS shield concept based on synthetic data, we here present a complete processing chain starting from actual GPS raw data and fully simulate the situation as it would be in a warning center. The procedure includes processing of GPS observations with predicted high precision orbits, inversion for slip and computation of the tsunami propagation and coastal warning levels. We show that in case of the Tohoku earthquake, it would be feasible to provide accurate tsunami warning as soon as 3 min after the beginning of the earthquake.

scholarly journals The unperceived risk to Europe's coasts: tsunamis and the vulnerability of Cadiz, Spain

2010 ◽  
Vol 10 (12) ◽  
pp. 2659-2675 ◽  
Author(s):  
J. Birkmann ◽  
K. v. Teichman ◽  
T. Welle ◽  
M. González ◽  
M. Olabarrieta
Keyword(s):  
Early Warning ◽  
Emergency Preparedness ◽  
Local Population ◽  
Warning System ◽  
Potential Threat ◽  
Adaptation Measures ◽  
Tsunami Early Warning ◽  
Tsunami Waves ◽  
The North ◽  
Reduction Strategies

Abstract. The development of appropriate risk and vulnerability reduction strategies to cope with tsunami risks is a major challenge for countries, regions, and cities exposed to potential tsunamis. European coastal cities such as Cadiz are exposed to tsunami risks. However, most official risk reduction strategies as well as the local population are not aware of the probability of such a phenomenon and the potential threat that tsunami waves could pose to their littoral. This paper outlines how tsunami risks, and particularly tsunami vulnerability, could be assessed and measured. To achieve this, a vulnerability assessment framework was applied focusing on the city of Cadiz as a case study in order to highlight the practical use and the challenges and gaps such an assessment has to deal with. The findings yield important information that could assist with the systematic improvement of societal response capacities of cities and their inhabitants to potential tsunami risks. Hazard and vulnerability maps were developed, and qualitative data was obtained through, for example, focused group discussions. These maps and surveys are essential for the development of a people-centred early warning and response system. Therefore, in this regard, the Tsunami Early Warning and Mitigation System in the North Eastern Atlantic, the Mediterranean, and connected seas promoted by the UNESCO-Intergovernmental Oceanographic Commission (IOC) should encompass these assessments to ensure that action is particularly intensified and fostered by those potentially exposed. That means that besides the necessary technical infrastructure for tsunami detection, additional response and adaptation measures need to be promoted – particularly those that reduce the vulnerability of people and regions exposed – in terms of national systems. In addition, it is important to develop emergency preparedness and awareness plans in order to create an integrated regional Tsunami Early Warning System (TEWS) by 2011. The findings of the paper are based on research conducted within the framework of the EC funded project TRANSFER: "Tsunami Risk ANd Strategies For the European Region", a project that aims to improve the understanding of tsunami processes in the Euro-Mediterranean region, to develop methods and tools to assess vulnerability and risk, and to identify strategies for the reduction of tsunami risks.

scholarly journals GPS water level measurements for Indonesia's Tsunami Early Warning System

2011 ◽  
Vol 11 (3) ◽  
pp. 741-749 ◽  
Author(s):  
T. Schöne ◽  
W. Pandoe ◽  
I. Mudita ◽  
S. Roemer ◽  
J. Illigner ◽  
...  
Keyword(s):  
Water Level ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Deep Ocean ◽  
Ocean Bottom ◽  
Tsunami Early Warning ◽  
Tsunami Waves ◽  
Gps Technology ◽  
Water Level Measurements

Abstract. On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements. The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS) (Rudloff et al., 2009) combines GPS technology and ocean bottom pressure (OBP) measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information. The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

Responses of a Tall Building in Los Angeles, California, as Inferred from Local and Distant Earthquakes

2016 ◽  
Vol 32 (3) ◽  
pp. 1821-1843 ◽  
Author(s):  
Mehmet Çelebi ◽  
Hasan S. Ulusoy ◽  
Nori Nakata
Keyword(s):  
Los Angeles ◽  
Transfer Functions ◽  
Tall Buildings ◽  
Tohoku Earthquake ◽  
The United States ◽  
The 2011 Tohoku Earthquake ◽  
Low Frequencies ◽  
Long Period ◽  
Period Effects ◽  
Story Building

The increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ∼350 km and 770 km, respectively, from the epicenter of the 2011 Tohoku earthquake. In California, very few tall buildings have been instrumented. An instrumented 52-story building in downtown Los Angeles recorded seven local and distant earthquakes. Spectral and system identification methods exhibit significant low frequencies of interest (∼0.17 Hz, 0.56 Hz, and 1.05 Hz). These frequencies compare well with those computed by transfer functions; however, small variations are observed between the significant low frequencies for each of the seven earthquakes. The torsional and translational frequencies are very close and are coupled. Beating effect is observed in at least two of the seven earthquake data.

scholarly journals First GPS TEC maps of ionospheric disturbances induced by reflected tsunami waves: The Tohoku case study

2016 ◽  
Author(s):  
L. Tang ◽  
Y. Zhao ◽  
J. An
Keyword(s):  
Gravity Waves ◽  
Arrival Time ◽  
Tohoku Earthquake ◽  
Internal Gravity Waves ◽  
Ionospheric Disturbances ◽  
Propagation Characteristics ◽  
Tsunami Waves ◽  
Travelling Ionospheric Disturbances ◽  
Ionospheric Height

Abstract. The straight tsunami waves from epicenter can be reflected when they reach to coasts or underwater obstacles. In this study, we present the first ionospheric maps of reflected tsunami signature caused by the great 11 March 2011 Tohoku earthquake using the dense GPS network GEONET in Japan. We observed tsunami-like travelling ionospheric disturbances (TIDs) with similar propagation characteristics in terms of waveform, horizontal velocity, direction, period and arrival time compared to the reflected tsunami at the sea-level, indicating the TIDs are induced by the reflected tsunami. The results confirm the atmospheric internal gravity waves (IGWs) produced by reflected tsunami can also propagate upward to the atmosphere and interact with the plasma at the ionospheric height.

Current Situation of Early Warning and Emergency Countermeasures of Volcanic Eruptions in China

2021 ◽  
pp. SP510-2020-135
Author(s):  
Wang Xinru ◽  
Pan Bo ◽  
Pan Mao ◽  
Liang Yiqiang
Keyword(s):  
Early Warning ◽  
Mainland China ◽  
Warning System ◽  
Volcanic Eruptions ◽  
The United States ◽  
Economic Losses ◽  
Government Response ◽  
The Government ◽  
Safety Systems

AbstractVolcanic eruptions, as one of major natural disasters, often cause considerable casualties and economic losses. Given the substantial potential hazards posed to society, volcanic eruptions have become a central concern for national public safety systems. This paper introduces the risk degrees and classification of activity of major active volcanoes in China, reviews early warning policies in the government response to volcanic eruptions, compares the early warning levels of China and the United States, and proposes an early warning theme adapted to the characteristics of volcanic activity in mainland China. The current volcanic warning system of China still has considerable room for improvement, therefore, improvements in monitoring volcanic activities and the anti-hazard capacity of volcanic eruption in the future are urgently needed.

scholarly journals The short-term tsunami forecast

2021 ◽  
Vol 946 (1) ◽  
pp. 012022
Author(s):  
Yu P Korolev
Keyword(s):  
United States ◽  
Early Warning ◽  
The United States ◽  
Kuril Islands ◽  
Express Method ◽  
Short Term ◽  
Tsunami Forecast ◽  
Tsunami Early Warning ◽  
Tsunami Forecasting ◽  
The Kuril Islands

Abstract A brief overview of the methods of a tsunami early warning in the Kuril Islands, which turned out to be ineffective during recent events, is presented. A hydrophysical method for short-term tsunami forecasting based on information about a tsunami in the ocean, used in the United States, and an express method, also using information about a tsunami in the ocean, are briefly described. The results of the retrospective forecast of the tsunami that occured on March 11, 2011, by the express method are presented.

scholarly journals Concept study of radar sensors for near-field tsunami early warning

2010 ◽  
Vol 10 (9) ◽  
pp. 1957-1964 ◽  
Author(s):  
T. Börner ◽  
M. Galletti ◽  
N. P. Marquart ◽  
G. Krieger
Keyword(s):  
Early Warning ◽  
Near Field ◽  
Warning System ◽  
Microwave Remote Sensing ◽  
Tsunami Early Warning ◽  
Tsunami Waves ◽  
Radar Sensors ◽  
Near Space ◽  
New Concepts ◽  
Remote Sensing Techniques

Abstract. Off-shore detection of tsunami waves is a critical component of an effective tsunami early warning system (TEWS). Even more critical is the off-shore detection of local tsunamis, namely tsunamis that strike coastal areas within minutes after generation. In this paper we propose new concepts for near-field tsunami early detection, based on innovative and up-to-date microwave remote sensing techniques. We particularly introduce the NESTRAD (NEar-Space Tsunami RADar) concept, which consists of a real aperture radar accommodated inside a stationary stratospheric airship providing continuous monitoring of tsunamigenic oceanic trenches.

Earthquake and Volcano Hazards Observation and Research Program: An Overview

2020 ◽  
Vol 15 (2) ◽  
pp. 70-75
Author(s):  
Naoyuki Kato ◽  
Takeshi Nishimura ◽  
◽  
Keyword(s):  
Research Program ◽  
Disaster Response ◽  
Tohoku Earthquake ◽  
Volcanic Eruptions ◽  
Fiscal Year ◽  
The 2011 Tohoku Earthquake ◽  
The Pacific ◽  
Volcano Hazards ◽  
Scientific Results ◽  
Volcanic Data

The Earthquake and Volcano Hazards Observation and Research Program was from Japanese fiscal year 2014 to 2018. This national program succeeded the Research Program for Earthquake and Volcanic Eruption Prediction (2009–2013). However, mainly because of the disaster caused by the 2011 earthquake off the Pacific coast of Tohoku, known as the 2011 Tohoku Earthquake, the basic policy of the program changed drastically. It changed from research for predicting earthquakes and volcanic eruptions to comprehensive research for mitigating disasters on the basis of scientific results related to the mechanisms of earthquakes and volcanic eruptions and their forecasts. The program was planned to be multidisciplinary in nature. In addition to Earth scientists working to get a scientific understanding of earthquakes and volcanic eruptions, historians, archaeologists, human and social scientists, and engineers took part in the program aimed at collecting pre-instrumental earthquake and volcanic data, understanding earthquake and volcano disasters, risk evaluation, and research into disaster response and preparedness. In this article, we review the basic concept of the 2014–2018 program and its main achievements. In the end, we summarize the problems left for future studies.

Sign in / Sign up

Export Citation Format

Share Document