Showing posts with label Hypocenter. Show all posts
Showing posts with label Hypocenter. Show all posts

Thursday, 16 June 2016

Hiroshima - 70 Years After The Atomic Bomb 広島被爆70周年


 
 
 
The Genbaku Dome ( Atomic Dome ).
Today the most iconic landmark in Hiroshima and a symbol of peace.

 

 

Everyone Should Visit Hiroshima .....




Hiroshima ( 広島 ) is a city in the Chugoku region of western Honshu, Japan. It was here, slightly more than 70 years ago during the final days of World War II, that the world's first atomic bomb was used by the United States against Japan in order to bring about an end to the conflict.

The atomic bombing completely obliterated the city and caused an estimated 140000 deaths, mostly civilians. But from the nuclear ashes, the resilient survivors had gradually rebuild their city into the modern metropolitan hub we are now familiar with. Hiroshima is today known as the City of Peace.

On 11th April 2016 John Kerry became the first US Secretary of State to visit the Hiroshima Peace Memorial Museum and Park as he attended the G7 Foreign Ministers Meeting in preparation for the G7 Summit the following month. At the museum, he was extremely moved by the " gut wrenching " displays that he saw and had this to say : " It tugs at all of your sensibilities as a human being. It reminds everybody of the extraordinary complexity of choices of war and what war does to people, to communities, countries, the world. ".

In addition, he said " Everyone should visit Hiroshima. And everyone means everyone. ". By that he meant everybody, including the Commander-In-Chief President Barack Obama, Nobel Peace laureate. Indeed, after a whole lot of deliberation by the White House, Obama did make a historical visit to the Peace Memorial Museum and Park during the G7 Summit, the first by a US President after the bombing. The only thing he didn't do was apologise.

With all that hype about Hiroshima, it would seem that I had heeded John Kerry's call when I visited the city on 8th Jun after participating in the Chitose JAL Marathon earlier. In actual fact, the visit was planned way before Kerry made that speech in April. I had wanted to go to Hiroshima not just for the Peace Memorial Museum and Park but also for the Yamato Museum and the Japan Maritime Self Defense Force Museum in Kure just 26km away. So here goes. All photos by the author unless indicated otherwise.



John Kerry's writing in the guestbook of the Hiroshima Peace Memorial Museum.
 Source @JohnKerry


Hiroshima Before The Atomic Bombing



Hiroshima is located at the mouth of the Ota River by the Seto Inland Sea ( 瀬戸内海 Seto Naikai ). It began as a feudal township hundreds of years ago with the construction of the Hiroshima Castle and gradually grew to become the leading castle town of the Chugoku and Shikoku regions during the Edo Period ( 1603 - 1867 ). Shortly after the Meiji Restoration ( 明治維新 Meiji Ishin ) of 1868, Hiroshima City was redeveloped as the capital of the newly created Hiroshima Prefecture. Strategically located with an abundance of resources from the land and the sea, it attracted schools and businesses and began developing thriving commercial districts. Unfortunately, the military was attracted to the city for the very same reasons that made Hiroshima appealing to the academia and industrialists. Starting from the early part of the 20th century, the greater Hiroshima area also become an important military district and the focus of Japan's ship building industry with many large vessels, military and civilian, being constructed at the nearby city of Kure.

During World War II, the city was a major military command centre ( HQ 2nd General Army ), logistics centre and embarkation point for troops fighting abroad with an estimated 40000 troops billeted there towards the end of the war. All these factors contributed to Hiroshima being identified as one of the designated atomic bomb targets. It was largely spared from the highly destructive incendiary bombing campaign of General Curtis Lemay in early 1945 mainly because the US wanted a more or less intact city to assess the destructive power of the atomic bomb. It had a population of 350000 in 1945.


The Atomic Bombing of Hiroshima



The United States and its allies the United Kingdom and Canada had been researching on atomic weapons in secrecy since 1939. Known as the Manhattan Project and directed by lead physicist Robert Oppenheimer, its aim was to produce the world's first atomic bomb, a super weapon that could level an entire city.

By late 1944 and early 1945, with America's island hopping strategy in the Pacific gradually pushing the Japanese forces further and further back towards their home island chains, the War was already a lost cause for Japan. However, the military high command showed no inclination to surrender and instead started mobilizing large numbers of civilians to defend the Home Isles in anticipation of an Allied Invasion sometime in late 1945 or early 1946.

At that time the results of high altitude daytime strategic bombing of Japanese cities with high explosive bombs were not encouraging due to inaccuracies induced by the jetstream. Even the subsequent incendiary bombing campaign which was highly destructive and killed 100000 people in a single night in Tokyo was not enough to persuade the Japanese generals to surrender.

On 16th July 1945, the United States successfully detonated the first atomic bomb in New Mexico. The War in Europe against Nazi Germany had already ended and the general public were getting increasingly war weary after six long years of global conflict. With the dateline for the Kyushu Invasion looming closer and faced with the prospect of a protracted war with an estimated 1 million Allied casualties, President Truman gave the green light for the use of nuclear weapons on Japan.

Months before, a special bombing group, the 509th Composite Group, had already been assembled and was training for delivering the atomic bomb to Japan. Due to the enormous size of the atomic weapon, the only suitable US aircraft that could possibly accommodate the bomb was the Boeing B-29 Superfortress  and even it had to have its bomb bays specially altered. The special bombing mission were to be launched from Tinian Island, part of the Northern Marianas Islands.

The primary and secondary targets for the atomic bombing were already pre-designated and unfortunately, for reasons already mentioned above, Hiroshima topped the list. Secondary targets were Kokura ( Kitakyushu ), Nagasaki and Niigata City.



Designated atomic bomb targets Hiroshima, Kokura, Nagasaki and Niigata.


6th August 1945


At 0145 hours, a trio of specially modified reconnaissance F-13As ( later designated RB-29A superfortress ) took off from Tinian headed for the primary and secondary targets of Hiroshima, Kokura and Nagasaki on a weather mission. That was followed one hour later by the bomb delivery B-29, the Enola Gay, piloted by the commander of the 509th Composite Group Colonel Paul W. Tibbets, and two accompanying B-29s whose purpose was for blast measurement instrumentation and strike observation and photography.

Over flying the Japanese cities in the early morning, the solitary F-13As attracted minimal attention from the Japanese air defenses. Just the night before, large groups of B-29 were picked up by Japanese early warning radars heading for various cities in southern Japan and the alert was issued in many cities including Hiroshima, with the all-clear given at 00:05 hours. Barely 7 hours later, another air raid alert went off in response to the weather reconnaissance aircraft at 7:09am but the all-clear was sounded at 7:31am. The citizens, weary from lack of sleep due to the moving in and out of air raid shelters the night before, started their daily routines. The message radioed from the weather aircraft to Tinian and Tibbets indicated that cloud over at all altitudes over Hiroshima was favourable and the advice was to bomb the primary target.

Thus, the fate of Hiroshima was sealed and the Enola Gay, visually identifying the streets of the city centre, made its bomb run at 8:09am local time, releasing the atomic bomb dubbed the " Little Boy " at 8:15am from an altitude of 31600 feet. The aiming point was the Aioi Bridge ( 相生橋 Aioibashi ) with an unmistakable T shape which was less than half a mile south-west of Hiroshima Castle.

The uranium bomb exploded at 8:16am at the pre-designated altitude of 1900 feet but missed the aiming point by 800 feet due to crosswinds. The airburst created a blast equivalent to 16 Kilotons of TNT which together with the intense heat and radiation instantly killed tens of thousands and completely destroyed everything within a one mile radius of the hypocenter ( 爆心地 bakushinchi ). Those further away were consumed by the resulting conflagration and more died.

The characteristic mushroom cloud created by the atomic blast rose to an altitude above 30000 feet, made up of smoke, soot and debris from the explosion. It could be seen even in Kure 26km away. Then came the Black Rain, another nuclear phenomenon where superheated vapour and gases cool down after rising to the upper atmosphere and then condense and fall back to earth as rain, mixed with radioactive fallout, dust and soot. In all, an estimated 4.4 sq miles or about 11 sq km of the city centre was totally destroyed by a combination of blast and fire.


The unique T-shaped Aioi Bridge ( aiming point ),
the Genbauku Dome and the Hypocenter.

 
 
Mushroom cloud over Hiroshima rising to 20000ft when this photo
was taken by the rear gunner of the Enola Gay. Photo : Wikipaedia


The Aftermath


The survivors of the initial nuclear explosion received little or no help in the initial hours and days after the bombing as most of the city's infrastructure and disaster response personnel were destroyed or killed and central authorities in Tokyo were slow to realize even the scale of the destruction. Resources were also stretched to the limit towards the last days of the war with everything in short supply from food to gasoline to medical supplies. It was not until after the second atomic bomb was dropped on Nagasaki 3 days later that the Japanese surrendered unconditionally on 15th Aug 1945.

Many of those who escaped the initial blast and fire would later succumb to their wounds and radiation sickness. More were to die in the subsequent months and years from a plethora of cancers directly related to the exposure to radiation.



Complete destruction at the city center after the atomic bomb, 1945. Photo : Wikipaedia

 
Peace Museum exhibit on plants sprouting
amidst the ruins, fall of 1945.



It was initially rumoured that the city would be barren and lifeless for 75years from the residual radiation, but a glimmer of hope came in autumn that year when the first plants began to sprout amidst the atomic ruins. Eventually, birds and other animals returned and the plants began to flourish and flower. The first plant to bloom after the bombing of Hiroshima was the Oleander ( Nerium oleander ) also known as キョウチクトウ (夾竹桃) or kyochikuto in Japanese. It brought hope and strength to the residents of Hiroshima as they struggled to rebuild their homeland. Because of that, the oleander was voted as the City Flower of Hiroshima in 1973. It blooms in the summer months, particularly around the anniversary of the atomic bombing in August, and the richly coloured blossoms always evoke deep emotions especially among the older generations and the Hibakusha (被爆者) - the survivors of the bomb.

Similarly the camphor tree ( Camphora cinnamonum ) or クスノキ( kusunoki 樟 ) was voted the City Tree of Hiroshima because many gaint ancient camphor trees used to grace the city especially around the shrines and temples. Most were destroyed by the bomb but those that managed to survive quickly recovered their vitality, symbolizing the will to live and the strength to rebuild for the survivors. Today, these evergreens are planted all over the city, bring colour to the parks and gardens throughout the four seasons, and testimony to the long and arduous path to recovery for an entire city.


The oleander was the first to bloom in Hiroshima after the atomic bombing.
It was voted the City Flower of Hiroshima in 1973. Photo : Wikipaedia


The Hiroshima Peace Memorial Park



In November 1946, it was decided that for the benefit of the citizens, an open park should be constructed in central Hiroshima out of the ruins where the busy commercial district once stood. By 1949 the concept of the park had evolved with the aim of promoting world peace and the site was to be near the hypocenter of the atomic bomb and were to include a peace boulevard as well. The designs were finalized and construction of the park began in 1951.

The Hiroshima Peace Memorial Park ( 広島平和記念公園 Hiroshima Heiwa Kinen Koen ) as it is now known opened on 1st Apr 1954. Its sprawling grounds hosts numerous memorials and monuments, museums and lecture halls, drawing more than a million visitors annually, and maybe even more after John Kerry's call for everyone to visit Hiroshima. They include the Peace Memorial Museum, the International Conference Centre, the National Peace Memorial Hall, the Peace Pond, the Memorial Cenotaph, the Peace Bells, the Peace Flame, the Children's Peace Monument, the Gates of Peace, the Atomic Bomb Memorial Mound, the Peace Clock, and many other installations.

The most notable structure within the Peace Park is of course the Hiroshima Peace Memorial, more common referred to as the Atomic Dome or the Genbaku Dome ( 原爆ドーム )  as it is known in Japanese. Gen means nuclear and Baku means explosion. It is the skeletal ruins of the former Hiroshima Prefectural Industrial Promotion Hall (広島県物産陳列館 ), designed by Czech architect Jan Letzel and completed in 1915. It is located by the banks of the Motoyasu River ( 元安川 motoyasugawa ), a branch of the Ota River as it cuts through the delta, just a stone's throw from Aioi Bridge and about 160m west of the hypocenter of the atomic bomb. It was one of the few structures that were left standing after the bombing as most other building structures constructed of wood and other less durable components were vapourised by the heat or blown to bits by the blast wave. The remnants of the building was preserved as a monument ever since and today serve as a symbol of peace, a strong reminder of the destructive nature of war and the call for global nuclear disarmament.



The Hiroshima Prefectural Industrial Promotion Hall during the Taisho Era. Wikipaedia


The Genbaku Dome as it appeared in Oct 1945.
Photo : Wikipaedia

 


How the Atomic Dome Survived the Nuclear Fires




The Genbaku Dome or A-Dome managed to escape complete destruction from the atomic explosion despite being almost directly at the hypocenter because of a few fortuitous factors.

First, European styled buildings of the colonial era ( construction commenced in1910 ) were generally solidly designed and built with masonry and durable materials like steel. Also, with earthquakes a common occurrence in Japan, these modern buildings were also generally better built to withstand such earth tremors.

The fact that it was almost directly at the hypocenter was perhaps the most important reason which prevented its complete destruction by the nuclear blast wave. Because the blast waves were coming from directly above the building, the concrete columns were able to withstand the longitudinal compressive force much better than a lateral stress.

The roof of the dome was constructed of copper plates which has a melting point lower than that of steel. Within 0.2 seconds of the detonation of the atomic bomb 600 meters above the dome, ground temperatures reached 3000°C and melted the copper plates. At 0.8 seconds after detonation, frontal shock waves reached the ground level with a supersonic speed of 440m/s and generated an enormous over-pressure of 3.5 MPa ( Megapascals ) or 35tons per meter square. The opening created by the melted roof plates allowed the blast wave to pass through the dome vertically without destroying the building completely.

Also, the many large glass windows of the building shattered immediately following the detonation and gave the blast wave an escape route without knocking all the walls down.

Therefore, although all 30 or so employees of the Department of the Interior ( Ministry of Construction ) within the building perished instantly in the ensuing fireball of the atomic blast, large portions of the building façade, though severely damaged, remained standing, much to the amazement of many.

The ruins were preserved in its original state after the bombing through the determined efforts of the people of Hiroshima. In Dec 1996, it was declared a UNESCO World Heritage Site.



Hiroshima Today



Alighting from the Shinkansen bullet train that brought me to Hiroshima, I couldn't help but noticed that this city was no different from other Japanese cities, with the usual hustle and bustle, the tall buildings, the clean and orderly streets with the occasional tram passing by and the rivers ... . All around me the city was teeming with trees and plants, and I even spotted an egret perching on a fence by the river bank as I made my way to the hotel on foot.



Egret by the Kyobashigawa River ( 京橋川 ) at the Kamiyanagi Bridge (上柳橋)
 south of Hiroshima Station.


Trams or shidens ( 市電 ) still ply the roads. This one was bound for Hiroshima Station.



If not for the prior knowledge on the history of Hiroshima, nobody would have guessed that 70 years ago, this exact city center was a nuclear wasteland. The numerous trees that lined the streets and the parks were lush and green this summer, no doubt benefitting from the incessant tsuyu ( 梅雨 ) or "plum rain", the seasonal rains of East Asia that prevailed in late spring and early summer every year. Many were mature trees with heights beyond 10 meters, even 20meters.

Walking towards the Genbaku Dome, I passed the grounds of the Art Museum, the Central Park and the rebuilt Hiroshima Castle. All were covered with greenery. Unfortunately I was in a hurry to beat the closing time of the Peace Memorial Museum and didn't have time for the castle ( or anything else ). It will have to wait for my next visit, hopefully soon if not next year.

Approaching the Atomic Dome near Ground Zero, the crowd began to get noticeably bigger. It was a strange feeling to be standing there, almost at the hypocenter, with everything intact, cars, shopping malls, restaurants, people and no radiation! Had the atomic detonation been a ground burst instead of an airburst, the story might have been very different and Hiroshima might have been uninhabitable for decades from the fallout.

At the A-Dome, people of all nationalities were represented. Some came in large groups, including school children, while many came in smaller groups. The mood was generally a little somber as the visitors read the inscriptions on the plaques and reflected on the tragic events that took place seven decades ago, and I didn't recall children screaming or running about.



View of the Genbaku Dome from the northern perimeter.


Plaque explaining about the A-Dome at the northern perimeter.




A-Dome from the western perimeter
by the banks of the Motoyasu River

 
 
Another view from the western perimeter


Description about the Dome being a UNESCO World Heritage Site
 at the southern perimeter.




After a quick tour of the Dome, I hurried to the museum before the closure at 5pm. There visitors were greeted with many photographic images, artifacts, audio-visual displays and 3D models relating to the atomic bombing of Hiroshima. Unfortunately, the East Wing of the museum was closed for renovations and the main building was really overcrowded and jam packed with visitors, many were Japanese high school students.


The Peace Flame with the Cenotaph and the Peace Memorial Museum
 in the far background.


Life-sized diorama of the severely burnt atomic survivors at the Peace Museum.


3D scale model of the city center of Hiroshima in relation to the
position of the atomic bomb ( represented by the red ball )
when it detonated on display at the Peace Museum.. 

 
Melted glassware, ceramics and metal ornaments on display at the Peace Museum.



Leaving the museum, I walked back towards my hotel but this time on the opposite bank of the Motoyasu River so that I could see the Genbaku Dome in its entirety from across the river. It was getting late in the afternoon and the tide was low, exposing the muddy bank at certain sections of the river. Somehow the winds also died down and created a calm mirror-like effect of the river surface, capturing the inverted image of the Dome in the river.



The Genbaku Dome and its reflection, view from across the Motoyasu River.



Another view of the Genbaku Dome and its reflection
in the Motoyasu River, from the Aioi Bridge.



The brief history of the Hiroshima Prefectural Industrial Promotion Hall
and an image of the building in its full glory before the bomb
was displayed on the opposite bank of the Motoyasu.
 
 
Another view of the Dome from the opposite bank.
 
 
 
Yes, drones are banned.
 
 
Approaching the Aioi Bridge, I passed a grove of a free flowering plants with beautiful pink flowers and I immediately recognized it to be oleanders, a plant which I was familiar with since childhood and which was also fairly common in the country of my residence. The combination of the forlorn Genbaku Dome in the background and a cluster of oleanders in full bloom in the foreground couldn't have created a more powerful image of both destruction and hope. Destruction on a scale that we wish no other city of the world would have to endure in the future. And hope that the world powers would one day move towards total nuclear disarmament and work towards achieving world peace.
 
 

 
The Genbaku Dome and Oleanders in full blossom, 8th Jun 2016.

 

A granite column somewhere within the Peace Park calling
for abolishment of nuclear weapons on planet Earth.
 地球上から核兵器廃絶 Chikyujo kara Kakuheiki Haizetsu

 
 
Logo from Hiroshima
City Website
 
 

As the 71st anniversary of the atomic bombing approaches, after a whirlwind stopover at Hiroshima, I must say that I completely agreed with John Kerry, that everyone should visit Hiroshima .... at least once. I know I'll be back.