Search

A multi-group of strong atmospheric waves (wave packet nos. 1–5) over China associated with the 2022 Hunga Tonga–Hunga Ha′apai (HTHH) volcano eruptions were observed in the mesopause region using a ground-based airglow imager network. The horizontal phase speed of wave packet nos. 1 and 2 is approximately 309 and 236 ms-1 , respectively, which is consistent with Lamb wave L0 mode and L1 mode from theoretical predictions. The amplitude of the Lamb wave L1 mode is larger than that of the L0 mode. The wave fronts of Lamb wave L0 and L1 below the lower thermosphere are vertical, while the wave fronts of L0 mode tilt forward above the lower atmosphere, exhibiting internal wave characteristics which show good agreement with the theoretical results. Two types of tsunamis were simulated; one type of tsunami is induced by the atmospheric-pressure wave (TIAPW), and the other type of tsunami is directly induced by the Tonga volcano eruption (TITVE). From backward ray-tracing analysis, the TIAPW and TITVE were likely the sources of wave packet nos. 3 and 4–5, respectively. The scale of tsunamis near the coast is very consistent with the atmospheric AGWs observed by the airglow network. The atmospheric gravity waves (AGWs) triggered by TITVE propagate nearly 3000 km inland with the support of a duct. The atmospheric-pressure wave can directly affect the upper atmosphere and can also be coupled with the upper atmosphere through the indirect way of generating a tsunami and, subsequently, tsunami-generating AGWs, which will provide a new understanding of the coupling between ocean and atmosphere. [ABSTRACT FROM AUTHOR]

Multi-group of strong atmospheric waves (wave packet #1-#5) over China associated with the 2022 Hunga Tonga--Hunga Ha'apai (HTHH) volcano eruptions were observed in the mesopause region using a ground-based airglow network. The phase speed wave packet #1 and wave packet #2 is approximately 312 m/s and 238 m/s respectively, which is consistent with Lamb wave L0 mode and L1 mode from theoretical prediction. The wave fronts of Lamb wave L0 and L1 below the lower thermosphere are vertical, while the wave fronts of L0 mode tilt forward above exhibiting internal wave characteristics, which show good agreement with the theoretical results. Two types of tsunamis were simulated, one type of tsunami is induced by the atmospheric pressure wave (TIAPW) and the other type tsunami is directly induced by the Tonga volcano eruption (TITVE). From backward ray tracing analysis, the TIAPW and TITVE were likely the sources of the acoustic-gravity waves (AGWs) accompanying wave packet #2 and wave packet #4-5, respectively. The scale of tsunamis near the coast is very consistent with the atmospheric AGWs observed by the airglow network. The AGWs triggered by TITVE propagate nearly 3000 km inland with the support of duct and persist for about 4.5 hr and almost covers the Chinese Mainland. The atmospheric pressure wave can directly affect the upper atmosphere, and can also be coupled with the upper atmosphere through the indirect way of generating tsunami and subsequently tsunami generating AGWs, which will provide a new understanding of the coupling between ocean and atmosphere. [ABSTRACT FROM AUTHOR]

Multi-group of strong atmospheric waves (wave packet #1–#5) over China associated with the 2022 Hunga Tonga–Hunga Ha'apai (HTHH) volcano eruptions were observed in the mesopause region using a ground-based airglow network. The phase speed wave packet #1 and wave packet #2 is approximately 312 m/s and 238 m/s respectively, which is consistent with Lamb wave L0 mode and L1 mode from theoretical prediction. The wave fronts of Lamb wave L0 and L1 below the lower thermosphere are vertical, while the wave fronts of L0 mode tilt forward above exhibiting internal wave characteristics, which show good agreement with the theoretical results. Two types of tsunamis were simulated, one type of tsunami is induced by the atmospheric pressure wave (TIAPW) and the other type tsunami is directly induced by the Tonga volcano eruption (TITVE). From backward ray tracing analysis, the TIAPW and TITVE were likely the sources of the acoustic-gravity waves (AGWs) accompanying wave packet #2 and wave packet #4–5, respectively. The scale of tsunamis near the coast is very consistent with the atmospheric AGWs observed by the airglow network. The AGWs triggered by TITVE propagate nearly 3000 km inland with the support of duct and persist for about 4.5 hr and almost covers the Chinese Mainland. The atmospheric pressure wave can directly affect the upper atmosphere, and can also be coupled with the upper atmosphere through the indirect way of generating tsunami and subsequently tsunami generating AGWs, which will provide a new understanding of the coupling between ocean and atmosphere. [ABSTRACT FROM AUTHOR]

This paper presents the first example of how to systematically identify the submarine landslide source of a tsunami using an innovative hybrid approach. This ground-breaking method is developed to resolve the puzzle around the source mechanism of the mysterious tsunami observed on 6th February 2023 in the Eastern Mediterranean Sea. The tsunami followed the two inland Mw 7.8 and Mw 7.5 Türkiye–Syria earthquakes, which occurred consequently with a 9 h interval on this day. The first earthquake (Mw 7.8) had an epicentral distance of 90 km from the nearest coast, which is closer than the second one (Mw 7.5) to the coast and yet its crustal deformation was almost entirely limited to inland. Therefore, the co-seismic surface displacement generated by the earthquake was ruled out as the source of the tsunami, confirmed by numerical modelling. Here, we hypothesized that the tsunami was most likely generated by a submarine landslide triggered by the earthquake. Analysis of tide gauge observations revealed that the waves arrived from 27 min to 48 min after the first earthquake (Mw 7.8) at different coastal locations, implying that the potential submarine landslide was triggered by the first earthquake (Mw 7.8). Backward tsunami travel time mapping using tide gauge observations guided us to constrain the area of the potential landslide. We approximated the dimensions of the landslide using spectral analysis of the tsunami observations. Consequently, an iterative trial-and-error approach was employed to confirm the landslide source of the tsunami by defining various informed alternative landslide scenarios and applying numerical modeling. Modelling showed that a submarine landslide can reproduce the tsunami observations reasonably well. It is located on a steep slope of the seafloor approximately 50 km from Arsuz. The submarine landslide is estimated to have caused a seafloor deformation measuring approximately 16 km in length and 4.0 km in width. [ABSTRACT FROM AUTHOR]

The complexity of the Kaikōura earthquake rupture and tsunami generation presented a unique opportunity to examine and learn from a modern event. This paper reviews how the five years of research following the Kaikōura tsunami have improved our understanding of the event and our knowledge of tsunami science across a range of disciplines. Teams of researchers and practitioners across disciplines of tsunami hazard modelling, palaeotsunami, risk and impact science, early warning, and emergency management learned from the event to calibrate models, enhance proxies for interpreting palaeotsunami deposits, and improve disaster risk readiness, reduction and response measures. While new scientific knowledge has been developed about the co-seismic hazard and risk facing Aotearoa-New Zealand, fundamental questions nonetheless remain about tsunami-generating sources and the likely return period for high impact events in Aotearoa-New Zealand. Further scientific endeavour is needed to investigate the onshore and offshore geological records to help improve understanding of tsunami hazard and history to underpin risk and impact assessments informing more effective disaster risk management. Lessons also emphasise a need for more effective partnership, participation, education, and engagement to increase local community capacity and capability to respond to local source tsunami events. [ABSTRACT FROM AUTHOR]