Geography – Rich Mineral Resources in the Northern Kitakami Belt –
The Sanriku region has geological strata spanning approximately 500 million years ago to the present, making it one of the few areas in Japan where the history leading to the current formation of the Japanese archipelago can be observed through these strata. Due to its rarity and other factors, Sanriku contains the area designated as “Sanriku Geopark,” one of Japan’s geoparks.
The inland areas of the Sanriku region are the relatively less steep Kitakami Mountains, with a fault line that divides two distinct strata—the northern Kitakami belt and the southern Kitakami belt—running near Mt. Hayachine almost at the center of the mountains.
The northern Kitakami belt is an accretionary body formed over a long period, approximately 320 to 140 million years ago, as oceanic plates subducted beneath continental plates. It was once the seabed near the equator, resulting in a complex mixture of various sediments. The strata of the southern Kitakami belt are older, ranging from approximately 500 to 200 million years ago, and some parts of the huge Gondwana continent, which was located in the southern hemisphere about 400 million years ago, have moved to their current position.
From the northern starting point of Hachinohe’s Kabushima, gentle marine terraces are visible for a while, and the difference in height between the sea and land gradually increases around Kitayamazaki in Tanohata Village. Near Hashikami, the cliffs are about 10 to 30 meters high, with shallow rocky areas and gentle grassy areas along the coastline. As you go south, the cliffs rise, reaching about 200 meters around the Kitayamazaki and Unosu Cliffs. These straight cliffs formed when the former seabed uplifted, eroding them linearly along the direction of the strata and cracks, resulting in their current appearance. The flat part on top of the cliff extends more than 10 kilometers east to west in some places.
The northern Kitakami belt is a treasure trove of minerals. Various mineral resources are abundant due to the formation of ore deposits through chemical reactions when magma erupted from the deep underground and came into contact with accretionary bodies. In particular, minerals such as sand iron and manganese are connected to the region’s life and industry, and traces of ancient iron-making sites have been found throughout the region.
In addition, in Kuji, amber, formed from resin accumulated in the soil approximately 90 million years ago, is mined, making it one of the few production areas in Japan. Furthermore, in Moshi, Iwaizumi Town, dinosaur fossils from the Mesozoic era, which were previously thought not to be found in Japan, have been discovered and named Moshiryu. In the inland parts of the same town, evidence of the largest mass extinction in Earth’s history, the P/T boundary, which occurred approximately 250 million years ago, can also be observed.
Vegetation – Diverse Vegetation along the Coastline –
In this area, diverse vegetation can be observed along the diverse coastline. Additionally, in early summer, the cold yamase wind blows in from the northeast, causing temperatures to drop nearly 10 degrees Celsius and fostering a dense fog, allowing the growth of plants typically seen at higher elevations. From the Ashige-zaki Observatory to the vicinity of the Nakasuga Coast is known as the Beach of Flowers. In early summer, wetlands bloom with irises, mountain peaks are adorned with nikko-kisuge, rocky areas flourish with daylilies and wild leeks, and sandy beaches are covered with beach plants like beach morning glory and beach rose.
The Osuka Beach, known for its “singing sand,” stretches for about 2 kilometers, with various beach plants dotting the sand dunes. Beyond the towering pines, many of them more than 100 years old, of Yodo-no-matsu, Tanesashi Beach is a natural turf habitat where horses were once pastured. Currently, natural turf and planted turf coexist here. The flatlands on the coastal terraces in northern Sanriku were once utilized as pastures and meadows. The gently sloping land of Hashikami-dake, now known as a place famous for azaleas, was once grazed by many cows and horses.
Around Uge, hikers walk along the sandy beach with many beach plants. At Fukkiri, white mugwort, beach roses, sea pink, and rare snakeroot are observed, and at the south side of Harashinai seagate, Sanriku Coast’s iconic beach roses and Mahatazao, listed in the Iwate Prefecture’s Red Data Book, bloom.
The surroundings of Samurai Beach are a habitat for Nambu Red Pine, and some of the groves contain naturally regenerated red pines. In the surrounding rocky areas, wild leeks, beach daisies, and bellflowers bloom. Northern Sanriku is putting effort into preventing the spread of oak dieback caused by pests infesting old oak trees, and within the broad-leaved forest, trees undergoing fumigation treatment covered in vinyl can be seen. Skunk lilies, affectionately known as Hamayuri, bloom in early summer at Kosode Beach.
Tofugaura Coast boasts efforts to conserve beach plants during the construction of seawalls after the Great East Japan Earthquake. The regeneration of plants, which were temporarily lost due to the tsunami, has progressed, and local residents, researchers, and elementary school students continue conservation efforts. Various colorful flowers, such as beach roses, beach peas, sea pink, and beach phlox bloom, as well as beach grass grow in clusters, thanks to efforts such as temporary transplant and root protection.
Around Fudai Watergate, pine trees were planted as a seawall forest following the lesson learned from the Showa Sanriku Tsunami of 1933, and it is said to have been effective in blocking debris during the tsunami caused by the Great East Japan Earthquake. Beach roses and beach phlox bloom on small sandy beaches.
The white-flowered rhododendrons seen on the cliffs of Kitayamazaki are rare to find on coastlines, as they usually grow on mountains on Honshu Island, making them a natural monument of Iwate Prefecture. At the disaster ruin at Meidohama Park, beach pea vines, beach peas, and beach primroses are seen around the remnants. Numanohama in the northern part of the Taro district of Miyako has nikko-kisuge and irises in the wetlands along with beach morning glory, beach peas, and beach phlox grow closer to the sea. Around Jodogahama Beach, there are beautiful red pine forests, with many of the plants that grow on islands constituting this scenic spot of red pine trees.
Towns – Nambu Domain and Route System –
*Nambu Clan ruled Hachinohe Domain and Morioka Domain
During the Edo period, the Pacific side of Tohoku was governed by the Hachinohe Domain, Morioka Domain, Sendai Domain, and Soma Nakamura Domain. The Hachinohe Domain, spanning from southern Aomori Prefecture to northern Iwate Prefecture, and the Morioka Domain, which extended across parts of Aomori, Iwate, and Akita Prefectures, were originally territories of the same Nambu family. They had deep historical connections and implemented a common Route (tori) System.
The Nambu clan originated from Kai (Yamanashi Prefecture today) and is said to have entered Mutsu during the Namboku-cho period. Among them the Sannohe Nambu clan built castles in places like Sannohe (Aomori Prefecture) and expanded their influence. After the reorganization of territories by Oshu Shioki, they expanded to the south. That was when the first lord, Nambu Nobunao, moved the castle to Morioka. When the third generation lord, Shigenao, died without a successor, the domain was divided among his two brothers, with Shigenobu receiving 80,000 koku of Morioka Domain and Naofusa receiving 20,000 koku of Hachinohe Domain.
Shigenobu established various systems to rebuild the domain that had now become 80,000 koku. One of them was the Route System, dividing the 10 counties and 587 villages within the domain into 33 routes, each overseen by a magistrate. These magistrates’ offices carried out administrative, judicial, and policing duties, such as investigating crop yields based on land survey records, managing the number of cattle and horses, and monitoring the movement of people to and from outside the domain.
The coastal areas consisted of Kuji Route in Hachinohe Domain and Noda Route, Miyako Route, and Otsuchi Route in Morioka Domain. Goods were gathered in the areas where the magistrates’ offices were located, and from there, marine products, salt, iron, and other items were transported to the castle town.