Events Calendar

Astani Civil and Environmental Engineering Seminar

Speaker: Prof. Masato Motosaka, International Research Institute of Disaster Science, Tohoku University, Japan

Talk Title: Lessons from the 2011 Tohoku Earthquake Focused on Ground Motion Characteristics and Building Damage

Abstract:
This paper describes lessons from the Tohoku earthquake focused on the building damage in relation to the observed ground motion characteristics from the engineering view points of the countermeasures against earthquakes. Although buildings with appropriate seismic retrofit were mostly escaped from free of damage,which indicates the effectiveness of the seismic reinforcement, it is suggested that total balance of the structural elements, the non-structural elements, and the equipment need to be considered. Also, the balance of foundation
and the superstructure for the comprehensive seismic performance of the whole building needs to be achieved. It
is important to investigate cumulative building damage for long-duration ground motion and seismic micro-zoning.
Keywords: The 2011 Tohoku Earthquake, ground motion, building damage, earthquake countermeasures

1 Introduction
A huge earthquake occurred in the Pacific Ocean off the coast of Miyagi, Japan on March 11, 2011 and caused huge physical damage and loss of life. The moment magnitude (Mw) of this earthquake, is 9.0, the largest recorded in Japan since modern seismograms became available. The fault plane has dimensions of 450km by 200km. The earthquake was followed by many aftershocks and also induced some other earthquakes.

The huge earthquake caused not only tremendous tsunami damage but also structural damage due to the severe ground motion which continued for sucha long duration. This earthquake has been named the 2011 off the Pacific coast of Tohoku Earthquake
(indicated as “the 2011 Tohoku earthquake” hereafter).

Although the 2011 Tohoku Earthquake took the human lives of about 18,000 persons mainly by tsunami, which closed up the evacuation problem, the status of vibration damage and lessons from the huge earthquake should be importantly informed for
countermeasures of urban and buildings against for the earthquakes in the future.

On March 11, 2011, the author experienced the severe shaking at 11th floor of 13-story building(seismic control building with oil damper braces) at Aobayama campus of Tohoku University in Sendai,Japan. From next day, the author started quick
damage survey and investigated ground motion characteristic and building damage and contributed to publish the damage survey reports by AIJ1) and summarized the lessons of the Tohoku earthquake focused on ground motion characteristics and
building damage 2). The author also contributed to the development and utilization of Earthquake Early Warning (EEW) system. The status of the EEW utilization during the Tohoku earthquake was reported together with the raised problems3). The author also has contributed recovery and reconstruction activities of local governments.

In this paper, lessons from the 2011 Tohoku earthquake focused on the building damage in relation to the observed ground motion
characteristics are described from the engineering view points of the countermeasures against the expected earthquakes in other area of Japan and other countries all over the world.

First, the observed ground motion characteristics are described regarding the observed high acceleration record, the impact of long-duration motions, and site dependent ground motions. Then, specific features of building damage are described.


Contact Author: Masato Motosaka, Professor, IRIDeS,
Tohoku University
Address: Aramaki-Aoba 468-1, Aoba-ku, Sendai
980-0845, Japan
Tel: +81-22-752-2117 Fax: +81-22-752-2119
e-mail: motosaka@irides.tohoku.ac.jp


Host: Dr. Maria Todorovska

Location: Seeley G. Mudd Building (SGM) - 101

Audiences: Everyone Is Invited

Contact: Evangeline Reyes