March 2011, Tsunami Disaster in Japan

The damage caused by the recent tsunami disaster in Japan is immeasurable and greatly influences the mental, socio-economic, political and cultural state of the country. This natural disaster results in serious disruption of the functioning of society, widespread human, material or environmental losses which exceed the ability of the affected society to cope using its own resources. Japan is an archipelago made up of many islands, of which there are four main ones namely Honshu, Shikoku, Hokkaido, and Kyushu. Japan is located in an area where several continental and oceanic plates meet which is the cause of frequent earthquakes and the presence of many active volcanoes and hot springs across the nation.

An offshore earthquake with moment magnitude of 9 struck at 05:46 UTC on March 11^th 2011 (named as the Tohoku Earthquake) is the biggest to hit Japan since late 1800’s as per the available records. Table 1 gives to the details of this great earthquake. It is ranked as the 5th largest earthquake in the world since 1900 and nearly 8,000 times stronger than one that devastated Christchurch (in New Zealand) in 2011 February. The quake shook dozens of cities and villages along a 2100 km stretch of coast. Figure 1 provides the MMI intensity map at different locations in Japan .When earthquake occurs below or close to the ocean it may result in causing tidal waves termed as Tsunami. Just over an hour after the earthquake, a tsunami was observed flooding Sendai Airport, which is located near the coast of Miyagi state. A 4m high tsunami hit Iwate State. Figure 2 represents the expected heights of tsunami wave as predicted by National Oceanographic and atmospheric administration (NOAA).This earthquake is followed by aftershocks around 124 detected near Japan's main island of Honshu and 111 events are with magnitude greater than or equal to 5.0. The main earthquake was preceded by a number of large foreshocks, beginning with 7.2 M_W events on 9^th March 2011 approximately 40 km from the main event, and followed by another three on the same day with moment magnitude of ≥ 6.

Japan lies on the "Ring of Fire", an arc of earthquake and volcanic zones stretching around the Pacific region where about 90% of the world's quakes occur, including the one that triggered the 26^th December 2004, Indian Ocean tsunami that killed around 230,000 people in 12 countries. The epicenter of the main quake is located off Miyagi state, about 370 km northeast of Tokyo. The earthquake occurred in the Japan Trench, where the Pacific Plate is subducting beneath the Okhotsk Plate. An earthquake of this size usually has a rupture length of at least 480 km and requires a long, relatively straight fault line. Because the plate boundary and subduction zone in this region is not very straight, earthquake magnitudes are usually expected to be up to 8 or above. The hypocentral region of this earthquake extends from offshore Iwate to offshore Ibaraki states. The earthquake released a surface energy of 1.9×10¹⁷ J, dissipated as shaking and tsunamic energy, which is nearly double than that of the 2004 Sumatra earthquake with 9.1 magnitude and killed 230,000 people. The total energy released is 3.9×10²² J, slightly less than the 2004 Sumatra earthquake. The total energy released underground is around 205,000 times that on the surface.

Table 1 Details of the 11^th March, 2011 Japan Earthquake (U.S Geological Survey)

Magnitude	9.0 (Mw)
Date-Time	Friday, March 11, 2011 at 05:46:23 UTC Friday, March 11, 2011 at 02:46:23 PM at epicenter
Location	38.322°N, 142.369°E
Depth	32 km
Region	Near the east coast of Honshu, Japan
Distances	29 km E of Sendai, Honshu, Japan 177 km E of Yamagata, Honshu, Japan 177 km ENE of Fukushima, Honshu, Japan 373 km NE of Tokyo, Japan
Location Uncertainty	horizontal +/- 13.5 km

Fig.1 Earthquake intensity map during 11^th March, 2011 event (http://www.boston.com/bigpicture/2011/03/massive_earthquake_hits_japan.html)

Fig.2. Height of the Tsunami waves (National Oceanographic and atmospheric administration)

Table 2 represents the observations recorded by Japan Meterological Agency (JMA) at different stations around the coastline of Japan following the earthquake. These observations included tsunami maximum readings of over 3 m at the following locations and times on 11 March 2011, following the earthquake at 14:46 JST. Japan has an unforgettable history of experiencing the most devastating earthquakes and tidal waves in the recent past also i.e., Kanto earthquake (1923) which killed over 1 lakh people and the Kobe earthquake (1995) which killed about 6,000 and injured 415,000 people.

Table 2 Tsunami wave heights recorded at different stations along Japan coastline (http://www.jma.go.jp/en/quake)

Time (JST)	Location	Wave Height (m)
15:12	Iwate Kamaishi-oki	6.8
15:15	Ofunato	3.2 or more
15:20	Ishinomaki-shi Ayukawa	3.3 or more
15:21	Miyako	4.0 or more
15:21	Kamaishi	4.1 or more
15:44	Erimo-cho Shoya	3.5
15:50	Soma	7.3 or more
16:52	Oarai	4.2

The combination of a stronger earthquake and tsunami in Japan has created extreme destruction to buildings, roads, factories, railway network, tall structures, dams, nuclear reactors and even some areas were in fires. During this 11^th March 2011 earthquake 2694 people died and 7,222 persons were missing. Airport runways were deluded and shipping containers were cascaded through the city of Sendai. Buildings collapsed and landslides were reported in several communities along the 2,100 km stretch of coastline. The Tokyo port has suffered slight damage, smoke rose from the buildings in port area with part of the port being flooded. Soil liquefaction occurred in Tokyo Disneyland's carpark area. About 46,000 buildings were estimated to be damaged, out of which 5,700 were collapsed in the country.

At Tohaku Electric Power Plant, fire broke out and one third of Kesennuma city is submerged by tsunami waters. The Fujinuma irrigation dam in Sukagawa ruptured, causing flooding and destroyed 1,800 homes downstream. At Fukushima Daiichi Nuclear Power Plant No. 1 and No. 3 reactor buildings exploded (Fig. 3) on the alternative days after the Tsunami which has damaged the power supply system to the nuclear plant and further resulted in the failure of cooling system which controls the reactions in the reactors. Substantial damage was caused to the reactor building, including the upper structure being largely destroyed with the building’s roof and side panels blown off. The climax of this tragic event was the melting down of two nuclear reactors, which also caused a chemical explosion that prompted immediate evacuations of the affected areas with over 200,000 people being evacuated, especially those who were within a 10km radius of the Fukushima II Nuclear Power Plant and a 20km radius of the Fukushima I Nuclear Power Plant.

Fig. 3 Fukushima Daiichi reactor before and after explosion
(http://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html?hp)

The three disasters in Japan, namely earthquake, tsunami and the nuclear leak are expected to drop the economy of Japan which is now struggling to rise after falling due to the crisis and high debt. Japan’s economic loss due to earthquake and tsunami is accounted to be nearly $ 171 billion

Italian Pride "The Leaning Tower of Pisa"

The Leaning Tower of Pisa is not just some cranky Disneyland tourist attraction. It is an architectural gem and would be one of the most important monuments of medieval Europe even if it were not leaning. Standing in the Piazza dei Miracoli, it is part of the complex of four major gleaming white medieval buildings comprising: the Cathedral (Duomo), its bell tower (the Leaning Tower), its Baptistry and the Cemetery (Camposanto).
As with the other buildings in the Piazza, the bell tower was intended to represent the civic pride and glory of the wealthy city state of Pisa and as such it is beautiful, unique and enigmatic. In 1990 the Tower was closed to the public because of fears for its safety and in the same year a Commission was established by the Italian Prime Minister to implement stabilization measures. There can be no doubt about the importance of such an operation to Pisa, to Italy and to World Heritage.


The eight-storey tower is 53.3 m high above ground level and weighs 14,500 metric tonnes. Its masonry foundations are 19.6 m in diameter and have a maximum depth of 5.5 m below ground level. The foundations sloped towards the south at 5.5 degrees to the horizontal and in 1990 the seventh floor overhung the ground by about 4.5 m. Construction is in the form of a hollow cylinder surrounded by colonnades. The inner and outer surfaces of the cylinder are faced with tightly jointed marble but the material between these facings consists of mortar and stones in which extensive voids have been found. A spiral stairway winds up within the walls of the Tower. The stability of the masonry at second-storey level on the south side has been a matter of major concern.
The underlying ground consists of three distinct layers. Layer A is about 10 m thick and consists of variable soft silty deposits laid down in shallow water (lagoonal, fluvial and estuarine conditions) less than 10,000 years ago. Layer B consists of very soft sensitive marine clays laid down up to 30,000 years ago which extend to a depth of 40 m. This stratum is laterally very uniform. Layer C is a dense sand extending to considerable depth.
The water table in Layer A is between 1 m and 2 m deep. The many soil borings around, and even beneath, the Tower show that the surface of Layer B is dish-shaped due to the weight of the Tower above it. From this it can be deduced that the average settlement of the Tower is about 3 m, which shows how very compressible is the underlying soil.


The vertical axis of the Tower is not straight – it bends to the north. In an attempt to correct the lean, tapered blocks of masonry were placed at the level of each floor to bend the axis of the Tower away from the lean. Careful analysis of the relative inclinations of the masonry layers has revealed the history of the tilting of the Tower.

The internationally accepted conventions for the conservation of valuable historic monuments require that their essential character should be preserved, together with their history, craftsmanship and enigmas. Thus any invasive interventions on the Tower had to be kept to an absolute minimum and permanent stabilisation schemes involving propping or visible support were unacceptable – and in any case could have triggered the collapse of the fragile masonry. Any temporary stabilisation measure had to be non-invasive and reversible.
Temporary stabilisation of the foundations was achieved during the second half of 1993 by the application of 600 tonnes of lead weights to the north side of the foundations via a post-tensioned removable concrete ring, cast around the base of the Tower at plinth level. This caused a reduction in inclination of about one minute of arc and, more importantly, reduced the overturning moment by about 10%. In September 1995 the load was increased to 900 tonnes in order to control the movements of the Tower during an unsuccessful attempt to replace the unsightly lead weights with temporary ground anchors. The masonry problem was tackled in 1992 by binding a few lightly post-tensioned steel tendons around the tower at the first cornice and at intervals up the second storey.A permanent solution was sought that would result in a small reduction in inclination by half a degree, which is not enough to be visible but which would reduce the stresses in the masonry and stabilise the foundations. Given that the foundation of the Tower was on the point of instability and that any slight disturbance to the ground on the south side would almost certainly trigger collapse, finding a method of reducing the inclination was far from straightforward and gave rise to many heated debates within the Commission. Many possible methods of inducing controlled subsidence of the north side were investigated. These included drainage by means of wells, consolidation beneath the north side by electro-osmosis and loading the ground around the north side of the Tower by means of a pressing slab pulled down by ground anchors. None of these methods proved satisfactory.

Sir Mokshagundam Visvesvarayya--"Father of Indian Civil Engineering"

Sir Mokshagundam Visvesvarayya popularly known as Sir M. V. (September 15, 1860–April 12, 1962), was an eminent Indian engineer and statesman. He is a recipient of the Indian republic's highest honour, the Bharat Ratna, in 1955. He was also knighted by the British for his myriad contributions to the public good. Every year, 15th September is celebrated as the Engineer's Day in India in his memory.

Foreword

Civil Engineering: The art and science of designing the infrastructure of a modern CIVILizedsociety.

It is considered as one of the oldest engineering disciplines, which involves planning, designing and executing structural works. The profession deals with a wide variety of engineering tasks including designing, supervision and construction activities of public works like roads, bridges, tunnels, buildings, airports, dams, water works, sewage systems, ports etc. and offers a multitude of challenging career opportunities.

A civil engineer requires not only a high standard of engineering knowledge but also supervisory and administrative skills. The major specialisations within civil engineering are structural, geotechnical, water resources, environmental, construction, transportation engineering etc.

IIT's in New Delhi, Mumbai, Chennai, Guwahati, Kanpur, Kharagpur are the most prestigious Engineering institutions in India.