EARTHQUAKES IN JAPAN MATEA GRGUREVI ZNANOSTI O OKOLIU

EARTHQUAKES IN JAPAN MATEA GRGUREVIĆ ZNANOSTI O OKOLIŠU

LOCATION • JAPAN HAS A TOTAL OF 6, 852 ISLANDS EXTENDING ALONG THE PACIFIC COAST OF EAST ASIA. • THE COUNTRY, INCLUDING ALL OF THE ISLANDS IT CONTROLS, LIES BETWEEN LATITUDES 24° AND 46°N, AND LONGITUDES 122° AND 146°E. • THE MAIN ISLANDS, FROM NORTH TO SOUTH, ARE HOKKAIDO, HONSHU, SHIKOKU AND KYUSHU. • THE RYUKYU ISLANDS, WHICH INCLUDE OKINAWA, ARE A CHAIN TO THE SOUTH OF KYUSHU. • TOGETHER THEY ARE OFTEN KNOWN AS THE JAPANESE

BIGGEST EARTHQUAKES IN JAPAN • 5 - SANRIKU EARTHQUAKE, 1933 • THE EPICENTER WAS 290 KM OFFSHORE • 8. 4 MAGNITUDE • A LOT OF AFTERSHOCKS FOLLOWED • RESULTED IN A TSUNAMI THAT CAUSED THE MAJORITY OF THE DAMAGE • THE TSUNAMI REACHED 28. 7 M IN HEIGHT • THE TSUNAMI WAS ALSO RECORDED IN HAWAII WITH A HEIGHT OF 2. 9 M

BIGGEST EARTHQUAKES IN JAPAN • 4 - ANSEI-NANKAI EARTHQUAKE, 1854 • 8. 4 MAGNITUDE • AT THE TIME, THE QUAKE WAS BLAMED ON A GIANT CATFISH, CALLED NAMAZU • ANSEI IS THE NAME FOR THE JAPANESE ERA SPANNING FROM 1854 TO 1860. • NANKAI IS THE NAME OF THE TROUGH WHERE THE EARTHQUAKE RUPTURED, SOUTH OF HONSHU. • THIS QUAKE HIT JUST ONE DAY AFTER SIMILARLY SIZED ANSEI-TOKAI EARTHQUAKE, WHICH KILLED 2, 000 PEOPLE.

BIGGEST EARTHQUAKES IN JAPAN • 3 - MEIJI-SANRIKU EARTHQUAKE, 1896 • MAGNITUDE 8. 5 • NEARLY IN THE SAME LOCATION AS THE 1933 EARTHQUAKE • THE EARTHQUAKE ITSELF WAS TOO FAR OFFSHORE TO CAUSE MUCH DAMAGE, BUT IT TRIGGERED A MASSIVE TSUNAMI. • THE TSUNAMI TRAVELED ACROSS THE PACIFIC OCEAN TO HAWAII AND CALIFORNIA.

BIGGEST EARTHQUAKES IN JAPAN • 2 - HOEI EARTHQUAKE, 1707 • MAGNITUDE 8. 6 QUAKE • TRIGGERED A TSUNAMI AND AT LEAST ONE LANDSLIDE • THE EARTHQUAKE RUPTURED ALL SEGMENTS OF THE NANKAI FAULT, THE ONLY EARTHQUAKE KNOWN TO HAVE DONE SO. • IT TRIGGERED AN ERUPTION OF MOUNT FUJI NEARLY 50 DAYS LATER

BIGGEST EARTHQUAKES IN JAPAN • 1 - TOHOKU EARTHQUAKE, 2011 • MAGNITUDE 9 • LASTED FOR ~6 MINUTES • SANDAI WAS THE NEAREST CITY TO THE EARTHQUAKE, ROUGHLY 130 KM FROM THE EPICENTER • THE EARTHQUAKE WAS PRECEDED BY A NUMBER OF LARGE FORESHAKES AND A LOT OF AFTERSHAKES • WARNINGS WERE SENT OUT 1 MINUTE BEFORE IT WAS FELT IN TOKYO, 8

BIGGEST EARTHQUAKES IN JAPAN • HTTP: //WWW. JAPANQUAKEMAP. COM/

BIGGEST EARTHQUAKES IN JAPAN • THE MEGATHRUST EARTHQUAKE WAS THE RECURRING MECHANISM OF THE SANRIKU EARTHQUAKE IN 1869 • THE EARTHQUAKE OCCURRED WHERE THE PACIFIC PLATE IS SUBDUCTING UNDER THE PLATE BENEATH NORTHERN HONSHU • THE ENERGY RELEASED FROM THE EARTHQUAKE COULD POWER A CITY OF THE SIZE OF LOS ANGELES FOR A YEAR

BIGGEST EARTHQUAKES IN JAPAN • 15891 CONFIRMED DEATHS, 2500 PEOPLE STILL MISSING • UNDER 2 HOURS AFTER THE EARTHQUAKE THE TSUNAMI HIT THE COASTLINE • UP TO 39 M IN HEIGHT AT MIYAKO CITY AND TRAVELED UP 10 KM INLAND IN SENDAI • THE TSUNAMI FLOODED APPROXIMATELY 561 SQUARE KM • THE TSUNAMI CAUSED A COOLING SYSTEM FAILURE AT THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT, WHICH RESULTED IN A LEVEL-7 NUCLEAR MELTDOWN AND RELEASE OF RADIOACTIVE MATERIALS.

• IN JAPAN, BUILDING STANDARD ACT HAS BEEN STRICTLY REVIEWED EVERY TIME THERE WAS A LARGE EARTHQUAKE. • ALL BUILDINGS ARE STRICTLY REQUIRED TO HAVE AN EARTHQUAKE RESISTANT STRUCTURE. • WITHOUT RIGOROUS COMPLIANCE TO EARTHQUAKE PROOF STANDARDS SET BY A LAW, ONE CAN NEVER GET AN APPROVAL OF CONSTRUCTION OF A BUILDING FROM A PUBLIC ADMINISTRATION OFFICE IN JAPAN. • IT IS SAID THAT THE COLLAPSE RATIO OF THE BUILDING AS A RESULT OF A POWERFUL EARTHQUAKE IS EXTREMELY LOW IN JAPAN COMPARED TO ANY OTHER COUNTRIES.

LEVEL OF EARTHQUAKE RESISTANCE BY STRUCTURE OF BUILDING • EARTHQUAKE RESISTANT STRUCTURE • IT IS THE MOST COMMON STRUCTURE FOR DETACHED HOUSES IN JAPAN. • ALL BUILDINGS BUILT AFTER 1981 MUST FOLLOW THE NEW ANTI-SEISMIC STRUCTURE STANDARD, REQUIRING BUILDINGS TO HAVE AN EARTHQUAKE RESISTANT STRUCTURE. • IN SUCH BUILDINGS, THE MAIN STRUCTURES (POSTS, WALLS AND FLOORS) RECEIVE SEISMIC MOTIONS. THE STRUCTURES CAN BE DIVIDED INTO RIGID STRUCTURES WHICH PREVENT THE BUILDING FROM COLLAPSING AND FLEXIBLE STRUCTURES THAT CAN BEND IN ORDER TO SPREAD THE FORCE OF SEISMIC MOTIONS.

• DAMPING STRUCTURE • IT PLACES DAMPING WALLS THAT ABSORB SEISMIC ENERGY WITHIN THE BUILDING IN ORDER TO MINIMIZE SEISMIC MOTIONS. • DAMPING STRUCTURES CAN BE DIVIDED INTO THE ACTIVE TYPE THAT USES ENERGY SUCH AS ELECTRICITY AND THE PASSIVE TYPE THAT USES PHYSICAL FORCES. • THE STRUCTURE REDUCES THE SEISMIC INTENSITY DOWN BY UP TO 70 - 80%

• SEISMIC ISOLATION STRUCTURE • THE STRUCTURE IS COMMONLY USED FOR HIGH-RISE BUILDINGS. • IT PLACES QUAKE-ABSORBING DEVICES (ISOLATORS) THAT BLOCK SEISMIC MOTIONS FROM REACHING THE BUILDING, AS PART OF THE FOUNDATION OF THE BUILDING. • THE QUAKE-ABSORBING DEVICES INCLUDE LEAD, SPRING, DAMPER, BALL BEARINGS, ETC. FURTHERMORE, NEWLY INVENTED CONSTRUCTION METHODS USE COMBINATION OF THESE MATERIALS. • THE STRUCTURE REDUCES THE SEISMIC INTENSITY DOWN TO 1/3 TO 1/5