Contents． 1
Papers and Reports． 1
1．S．OKUBO,The Variable Period Hypothesis and Q of the Chandler Wobble Reexamined．(in English) 1
2．T．MAKI,Effects of Observational Conditions on Hypocenter Location of Intermediate-Depth Earthquakes in Central Japan．(in English) 49
3．J．KASAHARA,S．NAGUMO,S．KORESAWA,Y．NISHI and H．SUGIMOTO,A Linear Trend of Hypocenter Distribution in the Outer Slope Region of the Japan Trench Revealed by OBS Array—Preliminary Report—(in English) 83
4．T．MIYATAKE,Great Earthquake Sequence along the Nankai Trough—A Hypothesis．(in Japanese) 105
5．T．UTSU,Seismicity of Japan from 1885 through 1925(Correction and Supplement)．(in Japanese) 111
6．S．NAGUMO,J．KASAHARA and S．KORESAWA,Position Accuracy of Pop-up Ocean-Bottom Seismometer．(in Japanese) 119
7．S．NAGUMO,J．KASAHARA,S．KORESAWA and H．MURAKAMI,Acoustic Release Ocean-Bottom Seismometer(ERI-AR81)．(in Japanese) 125
8．T．HATORI,I．AIDA,M．KOYAMA and T．HIBIYA,Field Survey of the Tsunamis Inundating Ofunato City—The 1960 Chile and 1933 Sanriku Tsunamis．(in Japanese) 133
9．T．MAKI,Residuals of Teleseismic P-wave Travel Times Observed in Japan．(in English) 151
10．T．MAKI,Numerical Estimation of Confidence Region of Fault-Plane Solutions．(in English) 193
11．T．HATORI,Philippine,Solomon and New Hebrides Islands Tsunamis Observed along the Coast of Japan,1971-1980．(in English) 221
12．S．IWASAKI,Experimental Study of a Tsunami Generated by a Horizontal Motion of a Sloping Bottom．(in English) 239
13．S．HONDA,H．FUJISAWA,T．UYEDA,Y．MATSUBARA and S．UYEDA,Development of a New Multiple Sensor Type Borehole Thermometer for the “Buried Thermistor Probe Method．”(in English) 263
14．S．HONDA,Numerical Analysis of Layered Convection——Marginal Stability and Finite Amplitude Analyses——(in English) 273
15．H．IMAI,Implosion Earthquakes Associated with the 1973 Eruptive Activity of Asama Volcano．(in English) 303
16．I．KAYANO,A Characteristic of Earthquake Sequences An Index for Energy Distribution of Major Earthquakes Belonging to Earthquake Sequences——(in Japanese) 317
17．I．AIDA and T．HATORI,Numerical Experiments of Tsunamis Inundating Owase City,Central Japan．(in Japanese) 337
18．H．TAKAHASHI,J．SATO and K．SATO,Environmental Radioactivity and Radon Content of Ground Water around the Fuji Volcano．(in Japanese) 351