catastrophic tohoku earthquake of march 11, 2011, in japan

ISSN 0747�9239, Seismic Instruments, 2012, Vol. 48, No. 1, pp. 1–9. © Allerton Press, Inc., 2012.Original Russian Text © A.A. Malovichko, O.E. Starovoit, I.P. Gabsatarova, M.V. Kolomiets, L.S. Chepkunas, 2011, published in Seismicheskie Pribory, 2011, pp. 5–16.

1

INTRODUCTION

A destructive, M = 8.8 earthquake occurred off thePacific coast of the Tohoku district (Honshu Island,Japan) on March 11, 2011, 05:46 UTC (14:46 Sakha�lin time) causing tsunami waves. The earthquake wasfollowed by numerous aftershocks. A strong earth�quake with a magnitude of M = 7.7 occurred in thesame area 2 days prior to the main shock, on March 9,2011, 02:45 UTC.

The Honshu area has been characterized by a highlevel of seismic activity since historical times. Theearthquake occurred in one of the most seismicallyactive areas of the Pacific coast of Japan. Strong earth�quakes accompanied by tsunamis have been known tooccur here before, as well. Thus, on June 15, 1896, theearthquake with a magnitude of M = 8.5 occurred tothe east of Honshu Island. The earthquake wasaccompanied by a tsunami with waves as high as 25 m.According to the data of the United States GeologicalSurvey, the death toll was 27000. On March 2, 1933,the Sanriku earthquake with a magnitude of M = 8.2occurred 178 km to the east–northeast from the areaof the Tohoku earthquake. It caused a tsunami withwaves as high as 28 m; the death toll was 3000 people(Gutenberg and Richter, 1948).

PARAMETERS OF THE MAIN SHOCKON MARCH 11, 2011

Parameters of the Tohoku earthquake were deter�mined on the basis of the data obtained from 70 sta�tions by the Alert Service, Geophysical Survey, Rus�sian Academy of Sciences (Fig. 1).

In near real�time mode, the waveforms werereceived from 42 stations, including two Japanese sta�tions (ERM and MAJO), the nearest to the epicenterRussian stations (YUK, KUR, YSS, VLA, KLR,SKR, PET), and South Korea station TJN. In addi�tion to the waveforms, urgent reports with macroseis�mic data were received. Twenty four automatically

highlighted reports from the international centers ofIDC CTBTO (International Data Center of the Com�prehensive Nuclear�Test�Ban Treaty Organization),IRIS�IDA (Incorporated Research Institutions forSeismology–International Deployment of Acceler�ometers), and KNDC (Kazakhstan National DataCenter), and four station reports from the stationsCLNS, ANN, MNK, and SIM were received via elec�tronic mail.

The hypocenter coordinates and magnitudes of theTohoku earthquake determined by the GeophysicalSurvey, Russian Academy of Sciences (GS RAS) andthe Sakhalin Branch of Geophysical Survey, RussianAcademy of Sciences (SB GS RAS) are listed inTable 1. The data on parameters of this earthquakereceived by the Geophysical Survey, Russian Academyof Sciences from a number of seismological centers arealso listed in Table 1. The locations of all epicenters areshown in Fig. 2.

According to the data of NEIC, CSEM, REBIDC, and GS RAS, the locations of the epicenters ofthe main shock are close and located within 20–30 kmfrom the epicenter determined by the Japan Meteoro�logical Agency (they are integrated into a single zonewith an ellipse). The same figure shows the location ofthe epicenter according to the preliminary data of theSB GS RAS, which was taken into account when thedecision of the necessity for alerting the possibility ofthe tsunami occurrence was made. The epicenterbased on the data of the Indonesian Center DJA,which was established after the destructive earthquakeon December 26, 2004, on Sumatra Island, is alsoshown in Fig. 2.

OPERATION OF THE TSUNAMI WARNING SYSTEM IN THE RUSSIAN FAR EAST

At the end of 2010, GS RAS introduced into ser�vice the next generation seismic subsystem within theTsunami Warning System (TWS) in the Russian Far

Catastrophic Tohoku Earthquake of March 11, 2011, in JapanA. A. Malovichko, O. E. Starovoit, I. P. Gabsatarova, M. V. Kolomiets, and L. S. Chepkunas

Geophysical Survey, Russian Academy of Sciences, pr. Lenina 189, Obninsk, Kaluga Obl., 249030 Russiae�mail: [email protected]

Abstract—The results of the comparative analysis of parameters of the Tohoku earthquake (Honshu Island,Japan) of March 11, 2011, 05:46 UTC and its aftershocks are presented.

Keywords: Japan, catastrophic earthquake, Tohoku earthquake, parameters.

DOI: 10.3103/S0747923912010082

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SEISMIC INSTRUMENTS Vol. 48 No. 1 2012

MALOVICHKO et al.

East. This subsystem underwent its first actual testingduring the earthquakes in Japan on March 9 and 11,2011.

This subsystem is a result of a 5�year�long elabora�tion within the framework of the project “Develop�

ment of the Network of Seismological Observationsand Instruments for Processing and Transmitting theData for Tsunami Warning” within the Federal goal�oriented program “Reducing Risks and Mitigation ofConsequences of Natural and Technogenic Emer�gency Situations in the Russian Federation before

Fig. 1. Location of the seismic stations that determined parameters of the earthquake on March 11, 2011, in the rapid mode.

Table 1. Comparison of parameters of the main shock according to the data obtained from different seismological centers

Center Date, time Latitude, °N Longitude, °E Depth, km Magnitude

GS RAN 11.03.2011 05:46:22

38.29 142.69 33 8.8 Ms

SB GS RAN 11.03.2011 05:46:25

38.60 142.10 33 8.4 Ms

NEIC 11.03.2011 05:46:24

38.32 142.36 32 9 Mw

IDC REB 11.03.2011 05:46:20

38.43 142.52 0 8.2 Ms

EMSC 11.03.2011 05:46:24

38.300 142.500 21.9 9 Mw

DJA 11.03.2011 05:46:26

38.560 142.880 44 8.4 Mw (mb)

JMA 11.03.2011 05:46:26

38.00 142.90 10 9.0 Mw

Note: GS RAS is the Geophysical Survey, Russian Academy of Sciences; SB GS RAS, Sakhalin Branch of the Geophysical Survey, Rus�sian Academy of Sciences; NEIC, National Earthquake Information Center, US Geological Survey; IDC, International Centerof the Comprehensive Nuclear�Test�Ban Treaty Organization, REB Bulletin; EMSC, European Mediterranean SeismologicalCenter; DJA, Indonesian Agency for Meteorology and Geophysics (BMKG); JMA, Japan Meteorological Agency.


CATASTROPHIC TOHOKU EARTHQUAKE OF MARCH 11, 2011, IN JAPAN 3

2010” (Chebrov et al., 2009, 2010; Gusyakov, 2010;Droznin and Droznina, 2010; Chebrov and Gusev,2010).

Eleven new seismic broadband stations were estab�lished within the subsystem, including five referencestations (Petropavlovsk�Kamchatski, Yuzhno�Sakha�linsk, Yuzhno�Kuril’sk, Ust’�Kamchatsk, Severo�Kuril’sk (Paramushir Island)) and six auxiliary stations(Vladivostok, Kuril’sk, Tilichiki, Okha, Nikol’skoe(Bering Island), and Malokuril’skoe (Shikotan Island))and 16 strong�motion seismic stations. The data fromall these stations are transmitted in real time to threenew regional data processing centers located in Petro�pavlovsk�Kamchatski, Yuzhno�Sakhalinsk, and Vladi�vostok. If a tsunamigenic earthquake emerges in theRussian Far East, the software designed especially forautomatic processing and analysis of seismic signals willmake a tsunami alert during the first few minutes after itis recorded by seismic stations.

On March 11, 2011, the decision on the necessityfor an alert for a possible tsunami was made 9.5 minafter the Yuzhno�Sakhalinsk station recorded thestrong seismic waves. In order to take preventive mea�sures that were necessary in this case, the correspond�ing information was sent to the following territorialtsunami warning centers: “Tsunami” Center of theSakhalin Territorial Administration for Hydrometeo�rological and Environmental Monitoring, Critical Sit�uation Management Center of the Russian Federa�tion, Ministry of Civil Defense and Emergency

Response in Sakhalin District, and Central Telegraphoffice, OAO Dal’svyaz’.

At 15:56, Sakhalin time, the warning “Prepare forthe tsunami” was transmitted. At 15:58, after theearthquake parameters had been refined, “Tsunamiwarning for all the Kuril Islands” was sent to the cen�ters mentioned above. According to the data of theRussian Federation, Ministry of Civil Defense andEmergency Response, approximately 11000 peoplewere evacuated from the area of possible flood risk; allrescuers were put on enhanced alert.

MACROSEISMIC EFFECTSON THE TERRITORY OF THE RUSSIAN

FEDERATION

The Tohoku earthquake was felt on the territory ofthe Russian Federation on the Kuril Islands: inYuzhno�Kuril’sk and Kuril’sk (with the intensity of4 on the MSK�64 scale) and in Malokuril’skoe settle�ment (3 on MSK�64). The intensities of the aftershockof March 11, 2011, 06:25 UTC (M = 7.2) felt inYuzhno�Kuril’sk and Kuril’sk with the intensity of5 and 4 on MSK�64, respectively. Tsunami waves wererecorded near Kunashir Island (in the proximity ofYuzhno�Kuril’sk) and near Shikotan and IturupIslands; their height reached 2 m.

SB GS RAS

GS RASSendai

CSEM

JMA

REB

DJA

NEIC

141° 142° 143°

39°

38°

39°

38°

141° 142° 143°

Fig. 2. Position of the epicenter of the Tohoku earthquake according to the data provided by different centers.

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MALOVICHKO et al.

MACROSEISMIC EFFECTS IN JAPAN

Small depth and the character of motion in theearthquake focus (upthrust along an almost verticalplane (80° to the horizontal) upon magnitude Mapproximately equal to 9.0) was the reason for the sub�sequent strong tsunami. The wave height was higherthan 10 m in certain regions of Honshu Island. Housesand cars moving along the roads were swept away bythe tsunami in some prefectures of Japan. A giant wavecovered the fields and roads and destroyed buildingsand constructions (Figs. 3a, 3b) (Petrov, 2011a,2011b).

Overland and air communications were interruptedwithin a considerable part of the country; the opera�tion of several nuclear and thermal power plants wasstopped. The tsunami caused total flooding of theflight strips of the Sendai airport. Severe fires started atthe oil refinery and gas constructions at a steel mill.Explosions occurred at Fukushima�1 nuclear powerplant; an evacuation was announced within a 20 kmradius.

According to the data provided by the RussianInformation Agency Novosti on March 28, 2011, thedeath toll was over 11000. The number of missing peo�ple was more than 17000. Thus, the total number ofdead and missing people caused by the natural disasterwas more than 28.3 thousand people.

THE ONSET OF SEISMIC ACTIVATION IN THE AREA OF THE TOHOKU EARTHQUAKE

A strong earthquake with M = 7.7 occurred 44 kmaway from the epicenter of the Tohoku earthquake inthe north�east direction on March 9, 2011, 02:45UTC, 2 days prior to the main shock. This earthquakewas accompanied by numerous aftershocks. GS RASdetermined the parameters of 40 aftershocks withmagnitudes 4.5–6.3 that occurred on March 9 and 10,2011.

Intense shocks in this focus were felt in half of theprefectures of Japan, including Tokyo. These shockscaused no casualties or serious damages. The partialcollapse of a school building was reported in one of thecities. High�speed train operation was stopped for sev�eral hours for safety reasons. The earthquake had noeffect on the operation of two nuclear power stationsin the Miyagi prefecture, which is located near the epi�center. The intensity of this earthquake felt in Yuzhno�Kuril’sk (Russia) was 2 MSK�64 scale.

The experts reported the warning of a tsunamiemergence; however, the height of waves caused bythis earthquake was as low as 60 cm.

According to the data provided by the InternationalCenter IDC CTBTO (Comprehensive Nuclear�Test�Ban Treaty Organization), the parameters of 116 after�shocks with mb > 3.5, which continued in this regionuntil May 11, 2011, 05:36 UTC, are known. Ten min�utes prior to the main shock of the Tohoku earth�quake, the shocks stopped and resumed after sometime with a lower energy and frequency of appearance.

ACCELOGRAMS OF THE TOHOKU EARTHQUAKE

The establishment of a network consisting of16 strong�motion seismic stations in the Russian FarEast (Fig. 4) enabled obtaining digital records of theaccelograms of strong earthquakes for the first time.

All strong�motion seismic stations are equippedwith CMG�5 accelerometers (GURALP). As opposedto the records made by velocimeters, the complete(without off�scale reading) record of the earthquakewas obtained in the accelerograms (Fig. 5).

AFTERSHOCKS OF THE TOHOKU EARTHQUAKE

After the main shock on March 11, 2011, 05:46 UTC,the parameters of more than 500 aftershocks with mb ≥ 5.0

(a) (b)

Fig. 3. Effects of the Tohoku earthquake: (a) fire and water: the houses in Natori that had been destroyed and swept off by a tsu�nami wave are on fire (Reuters/Kyodo); (b) the road bed in Satte, Saitama Prefecture destroyed by the earthquake (SaitamaShimbun/Assotiated Press/Kyodo News). The pictures were taken on March 12, 2011.



52°

48°

44°

142° 146° 150°

Stations for recording strong

Okha

Nogliki

Tymovskoe

UglegorskLagunka

Kunashir Island

Yuzhno�Ural’sk

Airport

Golovnino

Dolinsk

KholmskNovo�Aleksandrovsk

Yuzhno�Sakhalinsk

Nevel’sk Korsakov

Kuril’sk

Malokuril’skoe

motions, seismic subsystem of TWS

Fig. 4. The network of strong motion stations in the Kuril–Sakhalin segment of the general network.

05:30

06:40

05:4005:5006:0006:1006:2006:30

NGL 1500 km

Tim

e (h

:min

)

05:30

06:40

05:4005:5006:0006:1006:2006:30

UGL 1200 km

Tim

e (h

:min

)

Fig. 5. Fragments of the records of March, 11, 2011 made by accelerometers at Uglegorsk (UGL) and Nogliki (NGL) stationson Sakhalin Island.

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MALOVICHKO et al.

over the period from March 11, 2011 to March 29,2011 were determined at the Alert Service, GS RAS.The distribution of these aftershocks over the area isshown in Fig. 6. The size of the aftershock area wasapproximately 550 km in the longitudinal directionand 300 km in the transverse direction. The contoursof this area and the position of the main shock wereoverlay onto a similar map of aftershock distribution,according to the data obtained from the Japan Meteo�rological Agency (JMA) (Fig. 7). Thus, the resultsobtained in the operational mode at GS RAS are inclose agreement with the focal area determined basedon the data of JMA aftershocks.

JMA defines aftershock foci as lying within thedepths from several kilometers to 60 km (Fig. 7). Bothshallow and deep foci are located within small localareas. Most foci are located at a depth of 20–40 km.These depth values were confirmed by the IDCCTBTO Center (Vienna, Austria); the data on depthphases pP determined at a number of seismic stationswere published in the amended REB bulletin.

The aftershock process is still continuing. Accord�ing to the REB data of the International Center IDCCTBTO, more than 2500 aftershocks with mb ≥ 3.5were recorded during 4 days (March 11–14, 2011).

THE FOCAL MECHANISMOF THE TOHOKU EARTHQUAKE

The focal mechanism of the Tohoku earthquakewas calculated in the GS RAS using the signs of thefirst longitudinal wave arrival at 97 stations; compres�sion (+) and dilatation (–) waves were recorded at81 and 16 stations, respectively. The stations werelocated within the epicentral distances of 3°–83°, andthe azimuth distribution was appreciably uniform.Figure 8a shows the mechanism of the focus in stereo�graphic projection in the lower hemisphere, and themechanism elements are listed in Table 2. Table 2 andFigs. 8b and 8c show the solutions of the mechanismof the focus calculated using the centroid method atthe National Earthquake Information Center, USGeological Survey (USGS) and the method of tensormoment in the Global Centroid Moment Catalog(Global CMT Catalog), United States. The solutionsare virtually identical.

March 11, 2011

March 9, 201

Magnitude

aftershock area of theearthqua of March 9, 2011

March 11–29, 20114 5 6 7 8 9

35°

36°

37°

38°

39°

40°

41°

42°13

8°

139°

140°

141°

142°

143°

144°

145°

146°

35°

36°

37°

38°

39°

40°

41°

42°

Fig. 6. Location of the aftershocks of the earthquake ofMarch 11, 2011, according to the GS RAS data.

140° 145°

40°

35°

GS RAS

JMA

0 20 40 60Depth

Fig. 7. The distribution of the Tohoku earthquake ofMarch 11, 2011 with Mw = 9.0 over the area of aftershockswith M ≥ 4 over the period of March 11–23, 2011, accord�ing to the data of the Japan Meteorological Agency JMA[http://outreach.eri.u�tokyo.ac.jp/eqvolc/201103_toho�ku/eng]. The contour of the aftershock area is shown by ablack dashed line; the position of the main shock is shownby black contour (according to the data of the GS RAS).



The earthquake occurred as a result of both stretch�ing and compressing stresses oriented in the north�west–southeast direction. The northeast�strikingnodal plane is characterized by steep dipping (DP =78°–84°) and thrust with a dextral shear component.The second nodal plane is appreciably flat andstretches from the northwest to the southeast; over�thrust with the sinistral shear component (DP = 10°–19°) is of the motion type. The seismic moment of theTohoku earthquake calculated at the Information Pro�cessing Center (IPC), GS RAS based on the P�wavespectra obtained at four stations (Talaya (Δ = 30.27°),Arti (Δ = 56.09°), Obninsk (Δ = 67.69°), Kislovodsk(Δ = 70.84°)) M0 is equal to 3.5 × 1021 N m. The meanmoment magnitude Mw was calculated using the Kan�amori formula and was equal to 8.3.

According to the USGS data, the values of the seis�mic moment and moment magnitude M0 and Mw areequal to 2.8 × 1022 N m and 8.9, respectively. Accord�ing to the Global CMT data, the same parameters areas follows: M0 = 5.31 × 1022 N m and Mw = 9.1. M0 andMw values according to the IPC GS RAS differ fromthose based on the NEIC and CMT data because ofthe various method were used to calculate M0. Diffe�rent segments of the seismogram were used to calcu�late M0. Thus, only the longitudinal P�wave was usedat the IPC GS RAS, whereas the entire seismogram(all types of longitudinal and transversal waves, surfacewaves, etc.) was taken into account at other centers.

RECORDING LONG�PERIOD RAYLEIGH WAVES THAT RAN AROUND THE EARTH

During the earthquake of the magnitude compara�ble to that of the earthquake on March 11, 2011, therecords made at seismic stations equipped with high�sensitive instruments for recording long�period waves(e.g., STS�1) contained long�period mantle waves Rnthat ran around the Earth several times. These wavesare usually designated as follows: R1 – wave that trav�eled the shortest distance between the epicenter andthe station; R2 – wave that traveled from the epicenterto the station and back; R3 – wave that traveled thesame way as wave R1 and ran around the Earth; R4 –wave that that traveled the same way as wave R2 and ranaround the Earth, etc.

For isolation, these waves were filtered using the0.002–0.005 Hz Butterworth band�pass filter, whichenables isolating the oscillations with the period T of200–500 s. Waves up to R7 (i.e., the waves that ranaround the Earth three times) can be clearly seen onthe records from the Arti station located at the epicen�tral distance of 56° (Fig. 9). The waves that ran aroundthe Earth four and five times are less distinct. Thetrains of these waves were recorded every 11220 s (3 h7 min). Thus, the group velocity of the Airy phase oflong�period waves VRn with the period of approxi�mately 210–230 s is equal to 3.56 km/s.

It was demonstrated by comparing with theselected run�around waves caused by the Sumatraearthquake on December 26, 2004, with magnitudeM = 8.8 recorded at the Arti station that the directionof the highest energy release from the focus withrespect to the Arti station was different (Fig. 10). Thefocus was more asymmetric and the amplitudes of oddwaves were considerably higher compared with thoseof the even waves in the case of the Sumatra earth�quake. This means that the amount of energy releasedin the direction of azimuthal alignment for this stationwas higher than that released in the opposite direction.

CERTAIN MANIFESTATIONS OF SEISMICITY ACTIVATION IN 2011 PRIOR TO AND AFTER

THE TOHOKU EARTHQUAKE

The activation of certain Eurasia zones has beendetected since the beginning of 2011. The Trans�Asiandirection can be seen in the continental part: fromPakistan (an earthquake with M = 7.4 occurred onJanuary 18, 2011) through the Hindu Kush, where

(a) (b) (c)

Fig. 8. The focal mechanism of the Tohoku earthquakeaccording to the data of GS RAS and NEIC (a), USGS (b),Quick CMT (HRVD) (c).

Table 2. Parameters of the focal mechanism of the earthquake of March 11, 2011

Principal stress axes Nodal planes

CenterT P N NP1 NP2

Pl Azm Pl Azm Pl Azm Stk Dp Slip Stk Dp Slip

485555

322313295

363235

107108115

1811

0

210205205

141162203

191710

194588

332825

847880

108102

90

GS RAS NEIC HRVD

CMT

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MALOVICHKO et al.

04:00:00 08:00:00 12:00:00 16:00:00 20:00:00 00:00:00

Time (h:min:s)

R4R5

R1

R2R3

R7

11220 s

11220 s

ARU/bhz0011Mar1103:45:40

R1 R3

R2Station

Source

Fig. 9. Long�period mantle Rayleigh waves on the records made at Arti station (epicentral distance of 56°). The scheme of wavesthat ran around the Earth is shown on top.

12:00:00 16:00:00 20:00:00 00:00:00

Time (h:min:s)

R5

R1

R3

R6

R2

R4

R7

R7

R1

R2

R3 R4 R5

ARU/BHZ26Dec04

ARU/bhz0010Mar11

Fig. 10. Comparison of the wave pattern with the selected long�period mantle waves of the earthquakes of March 11, 2011, andDecember 26, 2004. The diagrams of the mechanisms of foci of these earthquakes are shown here.



intermediate�depth earthquakes occur, the PamirMountains, the Tian Shan, and Baikal to the AmurRiver region (Fig. 11). A series of earthquakes withmagnitudes mb = 4.3–5.0 occurred in the Amur regionon March 16–20, 2011. The strongest earthquakeoccurred on March 16, 2011, 17:12 UTC, and itsintensity in Khani Chara village was 3–4 and 3 on theMSK�64 scale, respectively. Such strong earthquakesare appreciably rare for this area.

A strong deep�focus earthquake of magnitude M =7.1 occurred on February 4, 2011, at the Myanmar�India border. Later, on March 24, 2011, a destructiveearthquake with M = 7.2 and the focus located in theEarth’s crust occurred 600 km southeastwards.According to the data provided by the Russian Infor�mation Agency Novosti, the number of deaths andinjuries caused by the earthquake was at least 60 and90, respectively. The earth shocks destroyed severaltens of residential buildings in the city Tarley.

CONCLUSIONS

The results of the rapid analysis of the dataobtained at GS RAS demonstrate their high informa�tion value. The large volume of conditioning digitaldata on the Tohoku earthquake is a good basis for per�forming a wide range of studies devoted to variousproblems of modern seismology and geodynamics.

REFERENCES

Chebrov, V.N., Gusev, A.A., Gusyakov, V.K., Mi�shatkin, V.N., and Poplavskii, A.A., Concept for Develop�ing a Seismologic Observation System for Tsunami Warningin the Russian Far East, Seism. Instrum., 2010, vol. 46,no. 3, pp. 275–285.

Chebrov, V.N., Droznin, D.V., Zakharchenko, N.Z., Mis�hatkin, V.N., Sergeev, V.A., Sinitsyn, V.I., and Shevchen�ko, Yu.V., Petropavlovsk Base Seismic Station for the Tsu�nami Warning Service, Seism. Instrum., 2011, vol. 47, no. 1,pp. 1–7.

Chebrov, D.V. and Gusev, A.A., Automatic Real TimeParameter Determination of Tsunami Earthquakes in theFar East of Russia: Algorithms and Software, Seism.Instrum., 2011, vol. 47, no. 3, pp. 225–240.

Droznin, D.V. and Droznina, S.Ya., Interactive DIMASProgram for Processing Seismic Signals, Seism. Instrum.,2011, vol. 47, no. 3, pp. 215–224.

Gusiakov, V.K., Magnitude–Geographical Criterion forOperational Tsunami Prognosis: Analysis of Application in1958–2009, Seism. Instrum., 2011, vol. 47, no. 3, pp. 203–214.

Gutenberg, B. and Richter, Ch., Seismicity of the Earth,New York: The Society, 1941.

Petrov, N., A Nine�Point Earthquake in Japan, Nauka vSibiri, 2011a, no. 11.

Petrov, N., The Great Disaster of Japan, Nauka v Sibiri,2011b, no. 12.

Magnitude

5 6 7 8 9

40° 40°

60°

0°80° 80°

60°

20°

0°

20°

0°

60° 120° 180° –120° –60°

–20°

–40°

–60°

–20°

–40°

–60°

0–33 34–70 71–160 161–300 301–500 >500

Depth, km

M < 4

Fig. 11. Seismicity of the globe in January–March 2011 based on the data by the Geophysical Service of the Russian Academyof Sciences.

catastrophic tohoku earthquake of march 11, 2011, in japan

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