Environmental Engineering Reference
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Fig. 10.3
The historical records of maximum tsunami inundation heights on the Sendai plain (
red
rectangles
and names) and in all areas of the Miyagi Prefecture (
black circles
and names)
To start the numerical model, we used the earthquake events available in the
historical records for the Sendai plain (Fig.
10.3
). The Miyagi-Ken Oki earthquake
was considered to be representative of M 7 class earthquakes. This earthquake was
modeled with variable fault parameters, following the Technical Reports of the
National Seismic Hazard Maps for Japan (NIED
2009
), and it is the most likely
class of earthquake, with a 99 % probability of occurring off the Miyagi coast every
30 years on average (Earthquake Research Committee
2005
). Next, the AD 869
Jogan earthquake tsunami (Minoura et al.
2001
; Sugawara et al.
2013
; Namegaya
and Satake
2014
) was modeled to represent M8 class earthquakes in the region.
Finally, the 2011 East Japan earthquake tsunami (Sugino et al.
2013
) was modeled
to represent M 9 class earthquakes, where the rupture area occupied almost all sec-
tions of the Japan Trench in front of the Tohoku and Fukushima coasts. These events
were then expanded by changing the tensor parameter for the single fault model (up
to 8.4 Mw) and up to 9.2 Mw for the multiple fault models, as shown in Table
10.1
.
The scenarios that used the single fault model were located mostly off the Miyagi
and Fukushima coast, while the scenarios with multiple fault models included areas
from northern Tohoku southward to Ibaraki Prefecture.
In total, 38 earthquake scenarios were modeled for the Sendai plain. Among
these, 26 cases were M 7 class earthquakes, which considered 21 scenarios based on
the probability analysis provided by NIED (
2009
). Nine cases were M 8 class earth-
quakes, and three cases represented M9 class earthquakes, including the 2011 event.
We modeled the seabed displacements using the formula provided by Okada (
1985
),
the results of which are given in Fig.
10.4
for earthquakes larger than 8 Mw.
Similarly, the historical earthquakes in the Tokai and Tonankai regions were
modeled as the basis for further scenarios in Owase City. The 1498 Meio earthquake
(M 8.6; Aida
1981a
), the 1605 Keicho earthquake (M 7.9; Aida
1981a
), the 1707
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