Trapped waves of the 27 November 1945 Makran tsunami: observations and numerical modeling |
| |
| Authors: | S Neetu I Suresh R Shankar B Nagarajan R Sharma S S C Shenoi A S Unnikrishnan D Sundar |
| |
| Institution: | (1) National Institute of Oceanography, Dona Paula, Goa, 403004, India;(2) The Institute of Mathematical Sciences, Chennai, 600113, India;(3) Indian Institute of Surveying and Mapping, Survey of India, Hyderabad, 500039, India;(4) Geodetic and Research Branch, Survey of India, Dehra Dun, 248001, India;(5) Indian National Centre for Ocean Information Services, Hyderabad, 500055, India |
| |
| Abstract: | The 27 November 1945 earthquake in the Makran Subduction Zone triggered a destructive tsunami that has left important problems
unresolved. According to the available reports, high waves persisted along the Makran coast and at Karachi for several hours
after the arrival of the first wave. Long-duration sea-level oscillations were also reported from Port Victoria, Seychelles.
On the other hand, only one high wave was reported from Mumbai. Tide-gauge records of the tsunami from Karachi and Mumbai
confirm these reports. While the data from Mumbai shows a single high wave, Karachi data shows that high waves persisted for
more than 7 h, with maximum wave height occurring 2.8 h after the arrival of the first wave. In this paper, we analyze the
cause of these persistent high waves using a numerical model. The simulation reproduces the observed features reasonably well,
particularly the persistent high waves at Karachi and the single high wave at Mumbai. It further reveals that the persistent
high waves along the Makran coast and at Karachi were the result of trapping of the tsunami-wave energy on the continental
shelf off the Makran coast and that these coastally-trapped edge waves were trapped in the along-shore direction within a
∼300-km stretch of the continental shelf. Sensitivity experiments establish that this along-shore trapping of the tsunami
energy is due to variations in the shelf width. In addition, the model simulation indicates that the reported long duration
of sea-level oscillations at Port Victoria were mainly due to trapping of the tsunami energy over the large shallow region
surrounding the Seychelles archipelago. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
