Definition of foreshock in English:



  • A mild tremor preceding the violent shaking movement of an earthquake.

    ‘a foreshock had been reported before the 1966 earthquake’
    • ‘The time between the last foreshock and the mainshock varies somewhat, but is typically less than a day.’
    • ‘This was the second major earthquake along this portion of the fault in less than two weeks - a magnitude 6.7 earthquake occurred a few miles to the west on October 23 and is now believed to be a foreshock of Sunday's massive quake.’
    • ‘Scientists are still studying foreshocks carefully to see if they can alert us to a possible bigger earthquake.’
    • ‘Even in areas where foreshocks are fairly common, there is no way of distinguishing a foreshock from an independent earthquake.’
    • ‘It apparently occurred without any significant foreshocks.’
    • ‘The short-term prediction was possible primarily on a series of foreshocks that began four days prior to the main shock.’
    • ‘Most people think of foreshocks as the small earthquakes that trigger a big quake.’
    • ‘A maximum probability gain of more than 20,000 is obtained if there are two or more foreshocks.’
    • ‘AGU is hosting a press conference on the 7.9 Denali earthquake that occurred on Nov. 3, 2002, in Alaska, as well as its Oct. 23, 2002, foreshock of 6.7.’
    • ‘Some have foreshocks signalling what is to come - but, as those so rudely awakened last night know only too well, others do not.’
    • ‘It was later discovered, though, that a rare series of small tremors, called foreshocks, occurred before the large quake hit the city.’
    • ‘The occurrence of foreshocks and aftershocks can be attributed to the nonconservative character of the Olami-Feder-Christensen model.’
    • ‘From historical accounts, the epicenters of the foreshocks were located in central California near the northwestern extent of the main shock fault rupture.’
    • ‘With the second model, accelerating fault slip on the mainshock nucleation zone triggers foreshocks.’
    • ‘A magnitude 6.7 temblor on Oct. 23 is now considered a foreshock.’
    • ‘At almost precisely 5: 12 a.m., local time, a foreshock occurred with sufficient force to be felt widely throughout the San Francisco Bay area.’
    • ‘Sensor data from the National Oceanic and Atmospheric Administration pinpointed the time and location of foreshocks and earthquakes.’
    • ‘Probably the most spectacular example was the short-term prediction of the 1975, M 7.3, Haicheng earthquake by the Chinese, based on earthquake foreshocks, unusual animal behaviour, and a few other precursors.’
    • ‘The study, reported in today's Nature, is the first to suggest that small seismic shocks or foreshocks preceding a major earthquake can be used in some cases to predict the main tremors.’
    • ‘The rate of main shocks after foreshocks follows the same patterns as aftershocks after main shocks.’
    earth tremor, tremor, convulsion, shock, foreshock, aftershock
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