K
香港政府
GIS
新聞處
PRH 7
DAILY INFORMATION BULLETIN
SUNDAY, MARCH. 14, 1976
KK ON THE WHOLE UNAFFECTED BY EARTHQUAKES
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FOUR HUNDRED AND TWENTY YEARS AGO, THE LARGEST KILLER EARTHQUAKE IN HISTORY STRUCK THE WEIHO VALLEY IN SHENS! PROVINCE, WREAKING HAVOC AND BRINGING DEATH TO 830,000 PEOPLE.
CLOSER TO US AND NEARER OUR TIME IN HISTORY, IN 1918, A TREMOR REGISTERING 7.0 ON THE OPEN-ENDED RICHTER SCALE OCCURRED IN SWATOW AND RIPPLED ACROSS 300 KILOMETRES TO HONG KONG.
ONE HOUSE ON. THE PEAK HAD TO BE VACATED, PENDULUM CLOCKS STOPPED AND GLASSES OVERTURNED, NO ONE HOWEVER WAS REPORTED TO BE INJURED.
HERE.
IT WAS APPARENTLY THE MOST SEVERE EARTHQUAKE EVER EXPERIENCED
+HONG KONG IS NOT ON THE CIRCUMPACIFIC SEISMIC BELT, WHICH IS A CIRCLE OF EARTHQUAKE AREAS SURROUNDING THE PACIFIC OCEAN, EXPLAINED MR. LAM HUNG-KWAN, SCIENTIFIC OFFICER IN CHARGE OF THE ROYAL OBSERVATORY'S SEISMOLOGY SECTION, AND THERE IS LITTLE LIKELIHOOD THAT HONG KONG WILL BE AFFECTED BY A MAJOR EARTHQUAKE.+
ON AVERAGE ABOUT 600 TREMORS ARE RECORDED EACH YEAR BUT MOST OF THEM ARE NOT FELT IN HONG KONG. AS FOR THOSE FELT IN HONG KONG, NEARLY ALL OF THEM ARE ONLY OF INTENSITY 1 TO 3 ON THE MODIFIED MERCALLI SCALE AND SELDOM REACH INTENSITY 5.
THE MODIFIED MERCALLI SCALE, HE POINTED OUT, IS A MEASURE OF HOW AN EARTHQUAKE IS FELT AT THE RECEIVING END. ABSOLUTE MEASUREMENT OF ITS ENERGY RELEASED AT THE EPICENTRE IS MADE ON THE RICHTER SCALE.
WHEREAS THE MAGNITUDE OF AN EARTHQUAKE ON THE RICHTER SCALE DEPENDS ONLY ON THE AMOUNT OF ENERGY RELEASED BY THE EARTHQUAKE, ITS INTENSITY IN HONG KONG ON THE MODIFIED MERCALLI SCALE ALSO DEPENDS ON THE DISTANCE OF THE EPICENTRE FROM HONG KONG AND THE INTERVENING EARTH STRUCTURE. A MAJOR EARTHQUAKE, FOR EXAMPLE, OF MAGNITUDE 7 ON THE RICHTER SCALE COULD HAVE LOW INTENSITY IN HONG KONG ON THE MODIFIED MERCALLI SCALE AND COULD HARDLY BE FELT.
ON THE MODIFIED MERCALL SCALE, TREMORS OF INTENSITY 3 MAY BE FELT INDOORS AND CAUSE VIBRATIONS LIKE THE PASSING OF A LIGHT TRUCK, THOUGH THEY MAY NOT BE RECOGNISED AS THOSE OF AN EARTHQUAKE.
VIBRATIONS OF INTENSITY 7, AS DURING THE 1918 SWATOW EARTHQUAKE, CAN BE NOTICED BY CAR DRIVERS, BREAK FURNITURE AND MAKE STANDING DIFFICULT.
+ALTHOUGH WE ARE ON THE WHOLE UNAFFECTED BY EARTHQUAKES, HONG KONG IS FULLY EQUIPPED TO REGISTER THEM, MR. LAM CONTINUED.
Issued by Government Information Services, Beaconsfield House, Hong Kong. Tel: 5-233191
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