Energy Release and Earthquake Characteristics

The event was recorded by 35 accelerographs situated at ground level covering the length of the 500 km (311 mile) rupture zone. Few megathrust earthquakes in the world have been as well recorded as this one. Table 3 presents peak ground accelerations (PGA) recorded at some of the accelerograph stations established and monitored by the University of Chile. A significant characteris­tic of the recorded accelerograms was the long duration of around 2.5 min [19], a relatively long ground shaking when compared to other earthquakes.

When comparing the frequency content of the Chile 2010 earthquake with others (like the Llolleo 1985 earthquake, in Chile) (Fig. 8), we see a greater rela­tive importance of low frequency components (larger periods). This is evident

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SOUTH

ATLANTIC

OCEAN

FM ЛІАНО HU AMOS

NIHUK

(WflM) y їЯі-f НТІЧЛ

FIG. 7—The red circle indicates the epicenter of the earthquake near the small town of Cobquecura, in the Maule province. Santiago is shown upper right.

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TABLE 3—Peak ground acceleration, PGA (g) recorded on Feb. 27 [19].

Station name

Maximum

north-south

acceleration

Maximum

vertical

acceleration

Maximum

east-west

acceleration

FCFM, center (greater Santiago)

0,165

0,138

0,163

Santiago, center (greater Santiago)

0,218

0,182

0,309

Maipu (greater Santiago)

0,561

0,240

0,478

Constitution (VIII region)

0,552

0,352

0,640

Angol (IX region)

0,928

0,281

0,681

as there was severe damage to non-structural elements (curtain walls excluded) in middle – and high-rise buildings (having larger periods) than evidenced in low-rise buildings.

Figure 9 reveals the response spectra of the recorded motions from San­tiago station and shows acceleration measurements exceeding the values rec­ommended by the current Chilean seismic code. These effects may have

FIG. 8—Accelerograms from two stations, one in the 1985 Llolleo quake and one from the 2010 Maule quake [20].

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5% DAMPED PSEUDO-SPECTRAL ACCELERATION – 2010 Mw 8.8 Chile Earthquake

STAT ON: SANT AGO Cerro Santa Luc a

Period. T (sec)

FIG. 9—Response spectra for Santiago Station [20].

contributed to the observed damage and structural failures in many high-rise buildings [20].