**(Reference 3)**

The seismic intensity scale used for observation of seismic intensity on Table 2-A-(6) of Article 1-2 of the Meteorological Operation Act. Regulations (Ordinance No. 101 of the Ministry of Transport, 1952) were stipulated as follows. Please note.

February 15, 1996 Kozo Ninomiya, Director-General, the Meteorological Agency

**JMA seismic intensity scale**

Scale | Instrumental seismic intensity | Scale | Instrumental seismic intensity |

0 | Below 0.5 | 5Lower | 4.5 or above and below 5.0 |

1 | 0.5 or above and below 1.5 | 5Upper | 5.0 or above and below 5.5 |

2 | 1.5 or above and below 2.5 | 6Lower | 5.5 or above and below 6.0 |

3 | 2.5 or above and below 3.5 | 6Upper | 6.0 or above and below 6.5 |

4 | 3.5 or above and below 4.5 | 7 | 6.5 or above |

(Note)

Instrumental seismic intensity* means the value calculated from the following
formula, as an index of seismic ground motion.

I = 2 log (a_{0}) + 0.94

I is the instrumental seismic intensity.

a0 is the maximum value of a that satisfies
Integral(w(t,a)dt)>=0.3

In this case, the integration range is in the duration of continuation
of seismic ground motion.

t = time (unit is seconds).

a is the parameter related to the rate of acceleration of seismic ground
motion.

(unit is centimeters per square second).

w(t,a) is the function: w(t,a) = 0 when v(t)<a,

and w(t,a) = 1 when v(t)>=a

v(t) is the vector-composed value (the unit is centimeters per square second)
of the acceleration of three orthogonal components of seismic ground motion
at t (values obtained by respectively multiplying the Fourier-transformed
values for each component by the values calculated according to the formula
in the right-hand column of the attached table, according to the type of
filter presented in the left-hand column of the same table, and then by
reverse Fourier-transforming them).

**Attached Table**

Type of filter and formula

Type of filter |
Formula |

Filter that represents the effect of period |
(1/f) |

High-cut filter |
(1 + 0.694y |

Low-cut filter |
(1 - exp (- f/0.5) |

(Note)

f is the frequency of seismic ground motion (unit is Hertz).

y is the value obtained by multiplying f by 1/10.

**Additional rules**

(Enforcement period)

1. The above notification will be enforced from the day of promulgation,
and shall be applied to earthquake observation that will be conducted on
April 1, 1996 (in the next clause, referred to as "application date")
and thereafter.

(Special case of application of the JMA seismic intensity scale)

2. As to the special case of application of the JMA seismic intensity scale,
there will be changes as follows in the table from the application date
until September 30, 1996.

From:

5 Lower |
4.5 or above and below 5.0 |

5 Upper |
5.0 or above and below 5.5 |

6 Lower |
5.5 or above and below 6.0 |

6 Upper |
6.0 or above and below 6.5 |

To:

5 |
4.5 or above and below 5.5 |

6 |
5.5 or above and below 6.5 |