Question: Who is recognized as a hero for his actions in the aftermath of a megathrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on Friday 11 March 2011?

Context paragraphs:
April 2011 Miyagi earthquake: The April 2011 Miyagi earthquake (Japanese: "2011 Miyagi Prefecture earthquake" (2011年 宮城県沖地震 , 2011-Nen Miyagi-ken-oki jishin ) ) was a magnitude 7.1 M earthquake, with an epicentre off the coast of Miyagi Prefecture, approximately 66 km east of Sendai, Japan.  The earthquake was classified as an aftershock of the March 11 Tōhoku earthquake, and occurred at 23:32 JST (14:32 UTC) on Thursday, 7 April 2011.

Japan Trench: The Japan Trench is an oceanic trench, a part of the Pacific Ring of Fire, in the floor of the northern Pacific Ocean off northeast Japan.  It extends from the Kuril Islands to the Bonin Islands and is 10554 m at its deepest.  It is an extension of the Kuril-Kamchatka Trench to the north and the Izu-Ogasawara Trench to its south with a length of 800 km .  This trench is created when the oceanic Pacific plate subducts beneath the continental Okhotsk Plate.  The subduction process causes bending of the downgoing plate, creating a deep-sea trench.  Continuing movement on the subduction zone associated with the Japan Trench is one of the main causes of tsunamis and earthquakes in northern Japan, including the megathrust Tōhoku earthquake and resulting tsunami that occurred on 11 March 2011.

April 2011 Fukushima earthquake: The April 2011 Fukushima earthquake (福島県浜通り地震 , Fukushima-ken Hamadōri jishin ) was a potent magnitude 6.6 M intraplate aftershock that occurred at 17:16 JST (08:16 UTC) on 11 April in the Hamadōri region of Fukushima, Japan.  With a shallow focus of 13 km , the earthquake was centred inland about 36 km west of Iwaki, causing widespread strong to locally severe shaking.  It was one of many aftershocks to follow the 11 March Tōhoku earthquake, and the strongest to have its epicentre located inland.

2004 Indian Ocean earthquake and tsunami: The 2004 Indian Ocean earthquake occurred at 00:58:53 UTC on 26 December with the epicentre off the west coast of Sumatra, Indonesia.  The shock had a moment magnitude of 9.1–9.3 and a maximum Mercalli intensity of IX ("Violent").  The undersea megathrust earthquake was caused when the Indian Plate was subducted by the Burma Plate and triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing 230,000–280,000 people in 14 countries, and inundating coastal communities with waves up to 30 m high.  It was one of the deadliest natural disasters in recorded history.  Indonesia was the hardest-hit country, followed by Sri Lanka, India, and Thailand.

2011 Tōhoku earthquake and tsunami: The 2011 earthquake off the Pacific coast of Tōhoku (東北地方太平洋沖地震 , Tōhoku-chihō Taiheiyō Oki Jishin ) was a magnitude 9.0–9.1 (M) undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on Friday 11 March 2011, with the epicentre approximately 70 km east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 29 km .  The earthquake is often referred to in Japan as the Great East Japan Earthquake (東日本大震災 , Higashi nihon daishinsai ) and is also known as the 2011 Tōhoku earthquake, and the 3.11 earthquake.  It was the most powerful earthquake ever recorded in Japan, and the fourth most powerful earthquake in the world since modern record-keeping began in 1900.  The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 m in Miyako in Tōhoku's Iwate Prefecture, and which, in the Sendai area, traveled up to 10 km inland.  The earthquake moved Honshu (the main island of Japan) 2.4 m east, shifted the Earth on its axis by estimates of between 10 cm and 25 cm , and generated infrasound waves detected in perturbations of the low-orbiting GOCE satellite.

Hideaki Akaiwa: Hideaki Akaiwa (born c. 1968 in Ishinomaki, Miyagi prefecture, Japan) is recognized as a hero for his actions in the aftermath of the 2011 Tōhoku earthquake and tsunami.

2002 Mindanao earthquake: The 2002 Mindanao earthquake struck the Philippines at 05:16 Philippine Standard Time on March 6 (21:16 Coordinated Universal Time on March 5).  The sixth most powerful earthquake of the year, it registered a magnitude of 7.5 and was a megathrust earthquake.  It originated near the Cotabato Trench, a zone of deformation situated between the Philippine Sea Plate and the Sunda Plate.  The entire country is characterized by a high level of volcanic and seismic activity.  The earthquake was responsible for 15 deaths and roughly 100 injuries.  Up to 800 buildings were damaged as a result, many from a flood generated by landslides and falling debris.  A tsunami followed the earthquake.

2012 Chiba earthquake: The 2012 Chiba earthquake (千葉県東方沖地震 , Chiba-ken Toho-oki Jishin , lit.  "Offshore Eastern Chiba Earthquake") occurred along the northeastern coast of Chiba Prefecture, Japan at 21:05 JST (12:05 UTC) on Wednesday, 14 March.  Although its epicentre lay just offshore near Chōshi city, the shallow magnitude 6.1 M earthquake produced considerable shaking inland through much of the Bōsō Peninsula and lower Ibaraki Prefecture.  It occurred as a result of normal faulting in a seismically quiet region, possibly in response to the magnitude 9.0 M 2011 Tōhoku earthquake.

2014 Iquique earthquake: The 2014 Iquique earthquake struck off the coast of Chile on 1 April, with a moment magnitude of 8.2, at 20:46 local time (23:46 UTC).  The epicenter of the earthquake was approximately 95 km northwest of Iquique.  The mainshock was preceded by a number of moderate to large shocks and was followed by a large number of moderate to very large aftershocks, including a M7.7 event on 3 April.  The megathrust earthquake triggered a tsunami of up to 2.11 m that hit Iquique at 21:05 local time (00:05 UTC, 2 April).  Similar-sized tsunamis were also reported to have hit the coasts of Pisagua and Arica.

1946 Nankai earthquake: The 1946 Nankai earthquake (昭和南海地震 Shōwa Nankai jishin) was a great earthquake in Nankaidō, Japan.  It occurred on December 21, 1946, at 04:19 JST (December 20, 19:19 UTC).  The earthquake measured between 8.1 and 8.4 on the moment magnitude scale, and was felt from Northern Honshū to Kyūshū.  It occurred almost two years after the 1944 Tōnankai earthquake, which ruptured the adjacent part of the Nankai megathrust.

Supporting paragraphs: Hideaki Akaiwa 2011 Tōhoku earthquake and tsunami
Answer: Hideaki Akaiwa