Seventh chord an augmented fifth, and an augmented seventh (i.e., a sequence of 3 major thirds, such as C–E–G–B), is a rarely used tertian seventh chord. The reason is that the augmented seventh interval is enharmonically equivalent to one entire octave (in equal temperament, 3 major thirds = 12 semitones = 1 octave) and is hence perfectly consonant with the chord root. The seven commonly used chords are: Seventh chords can also be constructed using augmented or diminished thirds. These chords are not tertian and can be used in non-tertian harmony. There are many (mathematically, 64) chords that can be built, however,
Tropical Storm Octave (1983) to clean up dried mud near some rivers. Many destroyed buildings were later rebuilt. Considerable experience was also gained on how to protect flood banks. Ever since Octave, most of southern Arizona has been a drought. Repair costs from Octave totaled $60 million. It is estimated that it took four months for floodwaters to recede across southeastern Arizona and portions of New Mexico. Tropical Storm Octave (1983) Tropical Storm Octave was considered the worst tropical cyclone in the history of Arizona. The origins of Tropical Storm Octave were from a tropical disturbance that formed south of the Gulf of Tehuantepec