Seismic Activity in Northern Japan and the Hokkaido Region

Apr 26, 2026, 22:54

Introduction

On April 27, a magnitude 6.1 earthquake occurred in the Hokkaido region of Japan, following a period of heightened seismic activity in the northern part of the country.

Main Body

The earthquake took place at 05:24 JST in southern Hokkaido, with the epicenter located approximately 18 kilometers west of Sarabetsu. The Japan Meteorological Agency (JMA) recorded a seismic intensity of '5+' in the central Tokachi region, while the United States Geological Survey (USGS) estimated the depth at approximately 80 to 81 kilometers. No tsunami warnings were issued following this event, and the USGS indicated that the risk to human life and property was minimal due to the low population density in the area east of Sapporo. However, the JMA noted an increased probability of landslides and rockfalls in areas that experienced significant tremors. This event occurred within a week of a larger seismic disturbance on April 20, when a magnitude 7.5 to 7.7 earthquake struck off northern Iwate prefecture. That earlier event resulted in six injuries and the observation of an 80-centimeter tsunami at Kuji port. In response to the April 20 event, the JMA issued a special advisory regarding the increased probability of a 'megaquake' with a magnitude of 8.0 or higher, stating that the likelihood of such an event was higher than baseline levels. While nuclear plant operators reported no abnormalities at the Higashidori, Onagawa, Fukushima Daiichi, and Fukushima Daini facilities, the Tohoku Shinkansen service was suspended between Tokyo and Shin-Aomori. From a geological perspective, Japan's high frequency of seismic events is attributed to its location on four major tectonic plates along the Pacific 'Ring of Fire.' The nation averages approximately 1,500 earthquakes annually, representing roughly 18 percent of global seismic activity. This vulnerability is historically evidenced by the 2011 magnitude 9.0 undersea earthquake, which resulted in approximately 18,500 deaths or missing persons and a nuclear meltdown at the Fukushima plant.

Conclusion

The current situation is characterized by ongoing monitoring by the JMA, with residents in northern regions advised to remain vigilant and avoid coastal areas while seismic advisories remain in effect.

Vocabulary Learning

epicenter (n.)

the point on the Earth's surface directly above the focus of an earthquake / 震央

Example:The epicenter of the recent quake was located near the coast.

intensity (n.)

a measure of the strength of an earthquake, often expressed on a scale / 震度

Example:The local authorities measured the earthquake's intensity at 5+.

probability (n.)

the likelihood or chance that a particular event will occur / 機率

Example:Scientists warned of the probability of another major quake.

tectonic (adj.)

concerning the structure and movements of the Earth's crust / 構造的

Example:Tectonic plates collide, causing seismic activity.

vulnerability (n.)

the state of being susceptible to harm or damage / 脆弱性

Example:The region's vulnerability to earthquakes is high due to its location.

Sentence Learning

The earthquake took place at 05:24 JST in southern Hokkaido, with the epicenter located approximately 18 kilometers west of Sarabetsu.

Reduced Relative Clause: The phrase "with the epicenter located approximately 18 kilometers west of Sarabetsu" acts as a reduced relative clause, giving additional detail about the epicenter's position without using a relative pronoun.簡化關係子句: 「with the epicenter located approximately 18 kilometers west of Sarabetsu」作為簡化的關係子句，提供震央位置的額外資訊，省略了關係代詞。

While nuclear plant operators reported no abnormalities at the Higashidori, Onagawa, Fukushima Daiichi, and Fukushima Daini facilities, the Tohoku Shinkansen service was suspended between Tokyo and Shin-Aomori.

Concessive Clause: The subordinate clause beginning with "While" introduces a concession, contrasting the lack of abnormalities at nuclear facilities with the suspension of the Shinkansen service.讓步子句: 「While nuclear plant operators reported no abnormalities…」這個讓步子句將核電廠無異常的情況與新幹線停運形成對比。

The nation averages approximately 1,500 earthquakes annually, representing roughly 18 percent of global seismic activity.

Participial Phrase: The participial phrase "representing roughly 18 percent of global seismic activity" modifies the preceding clause, indicating the proportion of earthquakes.分詞短語: 「representing roughly 18 percent of global seismic activity」作為分詞短語，修飾前句，說明日本地震占全球地震的比例。

This vulnerability is historically evidenced by the 2011 magnitude 9.0 undersea earthquake, which resulted in approximately 18,500 deaths or missing persons and a nuclear melt down at the Fukushima plant.

Relative Clause: The relative clause "which resulted in approximately 18,500 deaths or missing persons and a nuclear melt down at the Fukushima plant" provides additional information about the 2011 earthquake.關係子句: 「which resulted in approximately 18,500 deaths or missing persons and a nuclear melt down at the Fukushima plant」作為關係子句，補充說明2011年地震的後果。

From a geological perspective, Japan's high frequency of seismic events is attributed to its location on four major tectonic plates along the Pacific 'Ring of Fire.'

Fronted Prepositional Phrase: The prepositional phrase "From a geological perspective" is fronted to set the context before the main clause.前置介詞短語: 「From a geological perspective」作為前置介詞短語，置於句首以設定語境。