The powerful Arthur’s Pass earthquake of 1929 was the first of a series of nine strong earthquakes that were to cause serious damage and loss of life in New Zealand as it reeled from the effects of The Depression.
On the evening of Saturday the 9th of March 1929, many residents of the railway settlement at Arthur’s Pass were at the weekly dance. During a square dance just before 11 p.m., the middle of the roof of the hall appeared to descend by about half a metre and the walls suddenly bowed outward. With no warning rumble, the hall was plunged into darkness as a magnitude 6.9 earthquake struck nearby.
The dance hall was violently shaken and people were thrown to the floor. On regaining their senses and striking lights, they were relieved to find that the hall had not sustained serious damage despite being in some disarray.
In the town of Arthur’s Pass, chimneys collapsed, cupboards disgorged their contents and pipes burst, flooding houses. Houses were twisted and thrown from their foundations. Cracks up to 15 cm wide opened in roads, and fissures opened up in the railway yard and extended for three kilometres alongside the railway lines. Throughout the rest of the rainy night, there were loud roars and rumbles as rocks and boulders plunged down mountain sides during the frequent aftershocks.
The coming of daylight allowed residents to take stock. Bridges were out of alignment, and railway lines were twisted and undermined by slumped ground. With many houses uninhabitable, a relief train was hastily arranged to evacuate women and children to Christchurch – but they had to walk more than a kilometre to reach it.
The earthquakes caused great alarm in many of the towns on the West Coast, but damage there was lighter. Chimneys were toppled in Greymouth, Cobden and Reefton, and decapitated in Westport. In Christchurch, the old Provincial Council Chambers suffered severe damage, with one wall threatening to fall.
Residents of Timaru reported considerable alarm at feeling the two larger earthquakes, and the Waimate town clock was stopped at 10:50 p.m. The main shock and larger aftershocks were also strongly felt in Blenheim.
Back in Arthur’s Pass, it was estimated that more than 140 earthquakes were experienced during Saturday. Repair crews were sent to the settlement to restore the railway through to the West Coast, and this was completed on Sunday 11th. It would be several weeks before the road through the Otira Gorge re-opened due to massive slips, and tourist trips over the Pass were cancelled.
Despite the power of the earthquake and the damage it caused, no lives were lost. George Eiby in “Earthquakes” published in 1989, notes that the main earthquake was felt over the entire country, except the Northland Peninsula.
Earthquakes are not unusual in Arthur’s Pass, and most are light but shallow due to the structure of nearby faults, such as the Alpine Fault. Jefley J. Aitken in “Rocked and Ruptured,” IGNS, 1999 writes: “Strike-slip movement on the Kakapo Fault caused [the] magnitude 7 earthquake at Arthur’s Pass in 1929.” The next large, shallow earthquake in the area would be the magnitude 6.7 quake in 1994.