I previously reported the Mt=9.1 for the Indian

Ocean Tsunami of December 26, 2004.  This is the

report of the  Mt estimate for the another Indian

Ocean tsunami of March 28, 2005.  Now six data

are available.

For determining Mt we use formula, Mt = log H2 + log X + 5.55

(Ref. Abe, K., Phys. Earth Planet. Inter., 27, 194-205, 1981)

Mt: Tsunami magnitude

H2: Maximum crest-to-trough amplitude on tide gage record in m

X: Distance from epicenter to station along the shortest oceanic

     path in km

                          H2(m)  X(km)    Mt

Cocos Is., Australia     0.2    1600     8.1

Colombo, Sri Lanka       0.5    2000     8.6

Panjang, Indonesia       0.9    1320     8.6

Hanimaadhoo, Maldives    0.4    2600     8.6

Male, Maldives           0.2    2500     8.3

Gan, Maldives            0.3    2700     8.5

AVERAGE                                   8.45+/-0.21

Thus, Mt=8.5.  Note that this Mt value, 8.5, is consistent with

Mw=8.6 of the Harvard solution, and is smaller than Mt=9.1 of

the December tsunami.  The average ratio of tsunami heights

(= 10**(8.5-9.1)) is one-fourth of the previous tsunami.

Yours sincerely,

Abe, K.

ERI, Tokyo Univ.  March 30, 2005