Impact of the 2011 Tohoku Earthquake and Tsunami on Beach Morphology Along the Northern Sendai Coast

Abstract

At 14:46 JST on March 11, 2011 a magnitude 9.0 earthquake (2011 Tohoku Earthquake and Tsunami) occurred off the Pacific Coast of Miyagi Prefecture. This study investigated the extensive changes in beach morphology due to the earthquake and tsunami along the 15 km Northern Sendai Coast using remotely sensed data. The remote sensing analysis on the beach topography and coastal forest demonstrated the following notable characteristics of beach morphological change: erosion of the northern barrier at the mouths of the Nanakitagawa and Natorigawa Rivers; erosion at an old river channel; scour landward of the seawalls in the longshore direction; erosion and deposition in beach areas with detached breakwaters; and deposition in coastal forest areas. Linkage of the deposition in the forest areas with the damage type of coastal forests was observed. The impact of the 1250009-1Coast. Eng. J. 2012.54. Downloaded from www.worldscientific.com by UNIVERSITY OF QUEENSLAND on 08/16/15. For personal use only. K. Udo et al.earthquake and tsunami on the beach morphology was serious; roughly 60% of the study area was degraded by 0.2-0.5 m in elevation mainly due to land subsidence, and a total of 0.4 km 2 of beach area was eroded mainly due to erosion of the northern barrier at the mouths of the Nanakitagawa and Natorigawa Rivers. This study explores the geographical changes brought on by a tremendous earthquake and tsunami, which will help to elucidate the mechanisms of coastal forest destruction, beach erosion, and their interaction during tsunami events.

Nationwide Post Event Survey and Analysis of the 2011 Tohoku Earthquake Tsunami

“…The survey areas were gradually expanded to all of the Tohoku region after the middle of April. Survey groups measured local tsunami heights along the coast stretching 2,000 km from Hokkaido in the north to Okinawa in the south, with the exception of a 30 km zone around the Fukushima Daiichi Nuclear Power Plant [Watanabe et al, 2012;Ogasawara et al, 2012;Shimozono et al, 2012;Gokon and Koshimura, 2012;Kakinuma et al, 2012;Udo et al, 2012;Tanaka et al, 2012;Mikami et al, 2012;Sasaki et al, 2012].…”

Utilizing Sar and Multispectral Integrated Data for Emergency Response

“…More than 15,800 people were killed, 3,800 missing, and 5,900 were injured. More than 978,000 houses were damaged and destroyed (Udo et al, 2012). This study is focusing on the urban areas at the north-eastern Japan, along the coastline (Figure 1).…”

Effects of a Macro-Roughness Element on Tsunami Wave Amplification, Pressures, and Loads: Physical Model and Comparison to Japanese and US Design Equations

“…The 29 September 2009 South Pacific Tsunami and the 27 February 2010 Chilean Tsunami also caused substantial damage and loss of life in local villages [see Reese et al, 2011;Mas et al, 2012]. On 11 March 2011, the Tohoku Earthquake Tsunami caused severe damage to over 400,000 homes and catastrophic loss of life along the east coast of Japan [see Mimura et al, 2011;Mori et al, 2011;Udo et al, 2012;Suppasri et al, 2013]. The magnitude and extent of damage were surprising given Japan's extensive history of tsunamis and the sophisticated tsunami countermeasures and warning systems in the country [Zaré and Afrouz, 2012].…”