1968 Hyūga-nada earthquake
Encyclopedia
The 1968 Hyūga-nada earthquake (Japanese
: 1968年日向灘地震) occurred on April 1, 1968 at 09:42 local time (00:42 UTC). The earthquake had a magnitude of Mw 7.5, and the epicenter was located in Hyūga-nada Sea, off the islands of Kyushu
and Shikoku
, Japan
. The magnitude of this earthquake was also given as Mjma 7.5. A tsunami
was observed. 15 people were reported injured. The intensity reached shindo 5 in Miyazaki
and Kōchi
.
This earthquake was an interplate earthquake between the Eurasian Plate
and the Philippine Sea Plate. In this region, the Philippin Sea Plate is subducting beneath the Eurasian Plate. The subduction interface around this region include the Nankai Trough
and the Ryukyu Trench
.
This earthquake is the strongst event recorded in the Hyūga-nada Sea region. The maximum slip was estimated to be 4 m. It was estimated that, in the Hyūga-nada Sea region, earthquakes with magnitudes about 7.6 occur with a period of about 200 years, while earthquakes with magnitudes about 7.1 occur with a period of about 20 to 27 years. It has been pointed out that there is a tendency of occurrence of inland earthquakes in Kyushu before and after large interplate earthquakes in the Hyūga-nada Sea region.
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
: 1968年日向灘地震) occurred on April 1, 1968 at 09:42 local time (00:42 UTC). The earthquake had a magnitude of Mw 7.5, and the epicenter was located in Hyūga-nada Sea, off the islands of Kyushu
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
and Shikoku
Shikoku
is the smallest and least populous of the four main islands of Japan, located south of Honshū and east of the island of Kyūshū. Its ancient names include Iyo-no-futana-shima , Iyo-shima , and Futana-shima...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. The magnitude of this earthquake was also given as Mjma 7.5. A tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
was observed. 15 people were reported injured. The intensity reached shindo 5 in Miyazaki
Miyazaki Prefecture
is a prefecture of Japan located on the island of Kyushu. The capital is the city of Miyazaki.- History :Historically, after the Meiji Restoration, Hyūga Province was renamed Miyazaki Prefecture....
and Kōchi
Kochi Prefecture
is a prefecture of Japan located on the south coast of Shikoku. The capital is the city of Kōchi.- History :Prior to the Meiji Restoration, Kōchi was known as Tosa Province and was controlled by the Chosokabe clan in the Sengoku period and the Yamauchi family during the Edo period.- Geography...
.
This earthquake was an interplate earthquake between the Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
and the Philippine Sea Plate. In this region, the Philippin Sea Plate is subducting beneath the Eurasian Plate. The subduction interface around this region include the Nankai Trough
Nankai Trough
The Nankai Trough is a submarine trough located south of Japan's island of Honshū, extending approximately 900 km offshore. In plate tectonics, the Nankai Trough marks a subduction zone that is caused by subduction of the Philippine Sea Plate beneath Japan, part of the Eurasian plate...
and the Ryukyu Trench
Ryukyu Trench
The Ryukyu Trench is a 2,250 kilometer long oceanic trench along the southeastern edge of Japan's Ryukyu Islands in the Philippine Sea in the Pacific Ocean. It is located between northeastern Taiwan and southern Japan...
.
This earthquake is the strongst event recorded in the Hyūga-nada Sea region. The maximum slip was estimated to be 4 m. It was estimated that, in the Hyūga-nada Sea region, earthquakes with magnitudes about 7.6 occur with a period of about 200 years, while earthquakes with magnitudes about 7.1 occur with a period of about 20 to 27 years. It has been pointed out that there is a tendency of occurrence of inland earthquakes in Kyushu before and after large interplate earthquakes in the Hyūga-nada Sea region.