Archive for November, 2005

Earthquakes near Auckland

Wednesday, November 30th, 2005

Earthquakes near Auckland are unusual at the best of times, so its not surprising that the three earthquakes that have occurred near Waiheke Island in Auckland’s Hauraki Gulf in the past 24 hours are attracting considerable interest.

The first event reported by Geonet was a magnitude 2.5 event 8 km deep at 11:35 p.m. last night (Tuesday). Another magnitude 2.5 earthquake occurred at the same depth 19 minutes later. Island residents have reported clearly hearing the rumble of the earthquakes, which is hardly surprising late at night in an area that rarely experiences such events.

This morning, at 11:08, a magnitude 3.3 earthquake was recorded slightly deeper at 9 km.

The Auckland Regional Council and the Institute of Geological and Nuclear Sciences co-operate to monitor the Auckland volcanic field of approximately 50 volcanoes for volcanic and seismic tremors. The Auckland Volcano-seismic Monitoring Network (AVSN) has recorded and published 15 earthquakes in the Auckland area since December 20th, 1995. The previously most recent event reported by AVSN was on November 30th last year, the largest being a magnitude 2.7 event at a depth of 5 km in May 1998.

Auckland is New Zealand’s largest city, and the City Council’s website reported a “usually resident” population of over 1.1 million in 2001, comprising 31% of New Zealand’s total population.

Rimutaka Tunnel 1877

Wednesday, November 30th, 2005

The original Rimutaka Tunnel was pierced in March 1877, and newspapers of the time excitedly discussed the route that the railway would follow when it reached Featherston in the succeeding 12 months. At the time, it was estimated that more than 1 million bricks would be required to line the 576 metre-long tunnel.

Myth has it that, later that month, the project manager for the tunnel popped into the local brickmaker and plonked an order for a million bricks on the counter. The shopowner is reputed to have uttered a now familiar response ” … a brick!” at this windfall. Overhearing the conversation, the brickmaker’s cart-horse Neddy quit on the spot and was last seen heading for the Kaimanawas where he became famous for founding a dynasty.

Returning to reality, the original tunnel was host to the famous Fell Railway about which much is written elsewhere. The tunnel was replaced with a newer, more convenient tunnel of 8798 metres in 1955, and is now part of a popular walking and cycling track.

Raoul & Campbell weather stations remembered

Tuesday, November 29th, 2005

“Raoul Island, Raoul Island, Zulu Mike Echo Two Two
This is Wellington ZLX59
Transmitting one two one five two decimal five listening Wun Three Fife Eight Zero.
How do you copy, over?”
“Roger and Good Afternoon Raoul. Have you merit 4 this way with light QRN for November. Standby for Wellington Traffic, Over.”

Another weather sked begins.

Back in the 1970s and early 1980s, New Zealand’s outlying weather stations at Raoul Island in the Kermadecs to the north and at Campbell Island in the Southern Ocean were staffed by meteorologists. Weather readings were taken and encoded into blocks of five (from memory) digit numbers for transmission to “the Weather Office” at Kelburn in Wellington.

Every three hours, technical operators from the Overseas Radio Telephone Terminal at the Wellington Transmission Centre would set up a radio link with the island to allow the met. men (and later women) to relay the weather data by voice to Kelburn. On a good day (or night) if radio propagation suited, the islanders could make telephone calls to family and friends after they’d relayed the weather data.

It was a strict routine. Every 3 hours, at 10 past the hour. With each successive contact, the islands would alternate – If Raoul was first at 3 p.m. then Campbell was first at 6 p.m. and so on. Staff at the island holding second place could make private telephone calls but only after relaying the weather data to Kelburn. The weather data “must get through.” Business first, pleasure later.

When radio propagation was poor, an island was allowed to miss a scheduled contact, but people started to get jittery if they missed a second contact 3 hours later. In atrocious conditions, say during a solar outburst, when the radio conditions were abysmal, the technical operator would sometimes communicate with the island and take the weather data by using Q codes, the phonetic alphabet and clearly enunciated numbers where five was pronounced “fife” and nine pronounced “niner” etc. The data would then be telephoned through to Kelburn. Such situations were rare.

The Radio Terminal was located at the Wellington Transmission Centre through an historic anomaly when I worked there in the 1970s and 1980s. Toward the end of the period, the service transferred to Wellington Radio (ending a long dispute, I might add) but during my time it allowed me to take part in radio operating – something of an unexpected treat.

There were many humorous and dramatic events during my time there, and I hope to write up a few of them at some stage. Reprovisioning of the islands and crew changeover were always interesting times, and the odd scheduled contact would be missed. Other old friends would suddenly pop-up in “met territory” when perhaps one of New Zealand’s warships, for whom we also ran telephone schedules, would be visiting Raoul or Campbell.

An unexpected holiday was once declared when a yacht crewed by women called at Raoul Island. Much to the displeasure of the “brass” at Kelburn, met. work took a back seat to other pursuits while a “holiday” was declared, and the few weather skeds that took place involved more than a few shlurred words. I also noted that the pops and squeals that were normally associated with single sideband transmissions took on a different tone. 🙂

The occasional visits by the frigates Waikato, Otago and Canterbury to Campbell Island were also time for celebration, with the added bonus of litter – particularly in the form of the stubby beer bottles that were issued as part of the crew’s rations. These were pressed into service to hold Campbell Island Brew – an acquired taste. The staff at Campbell sent us one (it was well-travelled by the time it was ceremoniously handed over at the radio terminal in Wellington) and a group of technical operators assembled for a “formal tasting.” The cap was lifted and the noble beverage was carefully dispensed into eagerly held tasting glasses. Silence ensued. “Ah. Hmmm.” “Different.” “Good God!” “Hint of oranges..” “Three week old …” Well, never mind. I’m sure you get the picture. Meteorology was their speciality, not brewing. And anyway, the firewater that was produced depended on what was available on the island at the time. Fire was the important result in the cold winter months….

Nowadays, of course, automatic weather stations have replaced the teams of meteorologists at Raoul and Campbell. Raoul continues to be of interest to vulcanologists and seismologists owing to its close proximity to the Kermadec Trench, and is something of a dive spot. Campbell is visited less often, but is home to species of interest to conservation authorities. Scientific expeditions still use the accommodation once used by the pioneering met. folk.

In a Word

Monday, November 28th, 2005

An email arrived this week from an English relative who is proof-reading some of the chapters of my current book. He picked me up on my use of the word “stoush.”

I hadn’t realised that stoush is one of those words peculiar to New Zealand and Australia, and quickly confirmed (with the aid of the trusty Oxford dictionary) that it was indeed antipodean slang meaning “hit, fight with” and its origin was uncertain.

Well, “particularly nasty weather,” I thought. How many other New Zildisms have slipped into the text? Having taken a squiz at the dictionary to see if my English was crook, I sculled the coffee that I was drinking (it was smoko time), and realised that my use of English wasn’t too flash after all. What a dag!

As to the stoush. Well, I’d been rattling on about the Napoleonic Wars being the culmination of a centuries-long stoush between the English and the French. In my mind stoush = war, fight etc.

But in my rellie’s mind stoush meant zip. But, it was close to the Scots “stushie” which has a very similar meaning.

Maybe stushie climbed into the vernacular and became stoush during the pioneering days of the nineteenth century. If so, its a timely reminder of the rich heritage of the English, Irish, Scots, Maori, French and many others who have contributed to the building of our nation. We may forget them on a day-to-day basis, but they still pop up in our mannerisms, language, rituals and beliefs.

Anyway, I’d better rattle me dags and get on with the housework. Mum’ll be home from her girlie-session soon and she’ll give me ninga-ninga and throw a hissy if the dunny’s not clean, and then I won’t be allowed to pop down t’ the boozer for a Mac’s with me mates.

I’ll put that Peter Cape CD on while I get the electrolux out – I like that “Taumm-ranoooi, Taumm-ranoooi, Taumarunui on the main trunk line”… song, eh. The older sheilas like it, too.

Funny I should be thinking about icons and heritage at a time when they’re slowly disappearing. Even Vegemite. Jeez. Not made here any more, so Kraft tell me. Only made in Aussie since May. ‘Nuff to make ya spit the dummy!

February 2005 warmer, drier than previous two years

Monday, November 28th, 2005

With the proliferation of automatic weather stations, manual weather recordings for Tawa will cease at year’s end. Summaries of the readings taken over the 3 years to 2005 will be progressively published to provide background data for the recently installed automatic weather station.

These manual readings are obviously subjective, and represent the microclimate where the observations were made. However, gardeners might find the data of use in understanding germination, flowering and other crop problems.

Tawa’s climate during February 2005 was warmer, calmer and drier than the previous two years. February is normally our best summer month, and residents saw a welcome return to normal weather patterns after labelling 2004 as “the year without a summer.”

The maximum temperature was 30 or more degrees on 3 days early in the month, and rain fell on only 5. Wind was conspicuously absent and strong gusts were recorded on only 3 days. “Earthquake weather” as it used to be called by my elders when I was growing up on the East Coast. But mother nature was feeling benevolent, and the only event of note (apart from the nice warm days) was a magnitude 5.4 earthquake off the coast near Martinborough at 06:31 on February 1st which brought an end to two swarms of earthquakes which had plagued the region during January.

The seismic action moved north to the Bay of Plenty where two earthquake swarms, one near Kawerau the other near Matata began to play out. The Matata sequence of over 55 earthquakes would run until August, and become associated with local devastating floods – but that is outside the scope of this summary.

A summary of Tawa’s weather data for the three years is as follows:
The lowest February temperatures were 5 (2003), 6 (2004) and 9 (2005).
The average daily low temperatures were 13 (2003), 14 (2004) and 16 (2005).
The highest February temperatures were 28 (2003), 23 (2004) and 32 (2005).
The average daily high temperatures were 22 (2003), 20 (2004) and 24 (2005).

Days with frost: none (2003), none (2004), none (2005).
Days with rain: 6 (2003), 19 (2004), 5 (2005).
Days with thunderstorms: none (2003), 1 (2004), none (2005).
Days with hail: none (2003), none (2004), none (2005).
Days with strong winds: 6 (2003), 7 (2004), 3 (2005).

In keeping with the “year without a summer” label, February 2004 was host to two flood events. A foretaste of what was to come began on February 1st with steady rain by dawn. This soon escalated to heavy downpours and reports of surface flooding around the region began to come in by dusk. The weather then eased to drizzly, cloudy conditions with temperatures barely reaching into the 20s.

A severe weather warning was issued on Friday 13th February 2004 and the lower North Island braced itself. Gusty northerlies abruptly changed to the south at 5:30 p.m. and the rain commenced in earnest. The southerly rose to gale force and misty rain punctuated with downpours continued through Saturday 14th. Emergency services at Tawa were busy with lifting rooves and minor flooding events throughout the day.

The wind then rose to severe gale and the rain fell steadily on Sunday 15th. Whilst local emergency services continued their efforts, their counterparts further north in the Manawatu region were rushed off their feet. The town of Feilding was hardest hit by flooding and storm damage.

The storm conditions continued overnight Sunday – a night punctuated by the sound of mysterious objects being blown about and clanking roofing iron. The fire siren sounded several times – perhaps the volunteers were so tired that they were sleeping through their pager alerts. By Monday morning several local emergencies had been declared in the lower North Island, and many people had been evacuated.

In Tawa rooves had been lifted, trees were down, and surface flooding and several minor slips had blocked roads. The council became concerned that the Keneperu Stream might burst its banks – probably near Linden – for the first time since the Glenside flood protection scheme had been installed in the 1980s. Train and bus services were cancelled, and police asked commuters to delay their trips until after 10 a.m.

Further afield, the Hutt Valley was isolated from Wellington, hampering the evacuation of people from flooded homes. Further north there were evacuations at Feilding, Tangimoana, and Foxton Beach with many roads closed. Stop banks had been breached and the massive Moutoa Floodway had been activated to drain water from farmland and the Manawatu River out into the Tasman Sea north of Waitarere Beach, near Foxton. Damage estimates were put at $50 million. The Manawatu Gorge road would not re-open for months.

On Tuesday 17th, conditions eased at Tawa and the wind swung to the north. The situation further north was not so rosy. Flooding and storm damage continued to cause problems as far north as South Taranaki, the town of Scotts Ferry was underwater and the settlements of Tangimoana and Foxton Beach remained evacuated, damage estimates rose above $100 million and searches for missing people were being carried out.

On Thursday February 19th, another storm warning was issued. By dusk the northerly wind was gusting to gale force and steady rain was falling, growing heavier as a series of thunderstorms rolled in. For two hours the storms raged overhead, with lightning and instantaneous thunderclaps rattling glasses, crockery, doors and venetian blinds (I’m not kidding!). Gutters overflowed and surface flooding rapidly developed.
Conditions eased toward midnight.

Friday the 20th dawned fine with blustery northerlies, and wise residents who had heard yet another severe weather warning being issued took evasive action by clearing blocked gutters and drains, downed trees and slumped banks.

By 8 a.m. on Saturday the 20th winds were already gusting from the north. The wind abruptly rose to gale force at 9:15 accompanied by drizzly rain. Gusts up to 135 km/h were recorded around the middle of the day. At 4 p.m. the winds increased even further, and police were warning people to stay indoors as streets became blocked by fallen trees and power lines. By 6 p.m. a gust of 180 km/h had been reported at Mt Kaukau 10 km to the south of Tawa, and 20,000 people were without power. Many roads were closed, including State Highway 1 at Johnsonville.

Storm conditions eased during the evening, and rainfall did not reach the predicted 30mm feared with already sodden soils. So much for February 2004 – usually our brightest summer month. It really was “the year without a summer.”

January 2005 cooler, calmer than 2004

Sunday, November 27th, 2005

With the proliferation of automatic weather stations, manual weather recordings for Tawa will cease at year’s end. Summaries of the readings taken over the 3 years to 2005 will be progressively published to provide background data for the recently installed automatic weather station.

These manual readings are obviously subjective, and represent the microclimate where the observations were made. However, gardeners might find the data of use in understanding germination, flowering and other crop problems.

Tawa’s climate during January 2005 was slightly cooler and calmer than the same month in 2004. Weather data for January 2003 is incomplete.

Readings taken at Tawa:
The lowest January temperatures were 7 (2003), 10 (2004) and 8 (2005).
The average daily low temperatures were 13 (2003), 12 (2004) and 11 (2005).
The highest January temperatures were 29 (2003), 28 (2004) and 28 (2005).
The average daily high temperatures were 23 (2003), 19 (2004) and 18 (2005).

Days with frost: no data (2003), none (2004), none (2005).
Days with rain: no data (2003), 11 (2004), 10 (2005).
Days with thunderstorms: no data (2003), none (2004), 1 (2005).
Days with hail: no data (2003), none (2004), none (2005).
Days with strong winds: no data (2003), 7 (2004), 5 (2005).

January 2004, despite the odd bright day, is memorable for a windy and cloudy period that became known as Wellington’s “year without a summer”. It wouldn’t be until February that Wellingtonians knew how apt this label was to be.

January 2005 will be remembered for yet another region-wide flood event. At Tawa, the rain commenced as drizzle on the afternoon of Wednesday the 5th and steadily grew heavier, reaching a rain rate of 32 mm/hour at 8:55 p.m. By 11 a.m. on the 6th, 49mm of rain had fallen since commencement of the rain event. Further afield, there was flooding at Otaihanga on the Kapiti Coast and in the Hutt Valley, with houses being evacuated. State Highway 1 had been washed out at McKays Crossing, as had the North Island Main Trunk Railway line. The rain eased during the afternoon, and the weather at Tawa became partly cloudy and humid.

Rain began falling again on the morning of Saturday the 8th with 31mm of rain falling in the three hours to 10:30 a.m. at which point a maximum rain rate of 86 mm/hour was reached, causing gutters to overflow and abrupt surface flooding on soils already saturated from the event two days earlier. Most of that morning thunderstorms passed overhead, causing crockery to rattle in the cupboards with resounding thunderclaps.

The rain eased to showers by 1 p.m. bringing the rainfall total to 39mm but thunderstorms continued to pass overhead until mid-afternoon. By this time the Wellington region was yet again isolated from the rest of the North island with both roads north closed and surface flooding was reported at Paekakariki and in the Hutt Valley.

The rain eased to drizzle and stopped early on the morning of the 9th, allowing road and clean-up crews to begin their work in earnest.

Fortunately for residents, the soft clay soils had started to dry out by the time two swarms of earthquakes struck the region later in the month. The first commenced near Martinborough on the 18th January 2005, with the seven events getting progressively larger until the magnitude 5.4 quake of February 1st. The second swarm of 5 earthquakes commenced near Upper Hutt on January 21st. The largest member of this swarm which ended on the 23rd was magnitude 5.5

October 2005 warmer, drier than previous two years

Saturday, November 26th, 2005

With the proliferation of automatic weather stations, manual weather recordings for Tawa, Wellington will cease at year’s end. Summaries of the readings taken over the 3 years to 2005 will be progressively published to provide background data for the recently installed automatic weather station.

These manual readings are obviously subjective, and represent the microclimate where the observations were made. However, gardeners might find the data of use in understanding germination, flowering and other crop problems.

The lowest October temperatures were 0 (2003), 3 (2004) and 4 (2005).
The average daily low temperatures were 9 (2003), 9 (2004) and 9 (2005).
The highest October temperatures were 21 (2003), 19 (2004) and 22 (2005).
The average daily high temperatures were 16 (2003), 16 (2004) and 17 (2005).

Days with frost: 2 (2003), none (2004), none (2005).
Days with rain: 16 (2003), 16 (2004), 12 (2005).
Days with thunderstorms: none (2003), none (2004) 1 (2005).
Days with hail: 2 (2003), none (2004), 1 (2005).
Days with strong winds: 5 (2003), 5 (2004), 6 (2005).

Friday the 3rd of October 2003 was memorable for a dramatic storm which affected the lower North Island. The day commenced with steady rain and the northerly wind had risen to gale force by mid-morning. Steady rain continued throughout the day and a torrential downpour for 30 minutes in Tawa at 6 p.m. was symptomatic of weather conditions elsewhere in the region.

Whilst the wind eased from a northerly gale during the evening, gusts continued and a Convair freight aircraft crashed on the Kapiti Coast in storm conditions at about 9:30 p.m. By 11 p.m. Wellington was cut-off from the rest of the North Island by flooding at Plimmerton, Paekakariki and Lower Hutt. Passengers were stranded on commuter trains, and traffic on northern roads was at a standstill. The automatic weather station at Mana, north of Tawa, recorded 70mm of rain for the day, 20mm of which fell between 5:30 and 6:30 p.m.

During the night, a state of emergency was declared on the Kapiti Coast, following a flash flood at Paekakariki. Drizzly rain continued on the morning of October 4th and State Highway 1 remained closed between Paremata and Paraparaumu and State Highway 2 was still closed by slips on the Rimutaka Hill Road; Wellington’s isolation continued.

Drizzle with fine intervals continued on the 5th, but the storm conditions eased as the weather changed to the south, and temperatures fell. A hailstorm that evening seemed to be the storm’s last gasp, and Tawa residents awoke to find a ground frost with the thermometer sitting firmly on zero at 6:55 a.m. on the 6th. Cleanup operations were able to begin in earnest over the next three days of cool but dry weather before more rain fell on October 10th.

The Departmental Laptop

Friday, November 25th, 2005

The Capital Connection is a long-distance commuter service that runs between Wellington and Palmerston North. Every weekday morning, the sleepy-eyed commuters clamber aboard at Palmerston North just after 6 a.m. and the train sets off on its two-hour southward trip to Wellington, stopping at most stations to Paraparaumu, from where it is non-stop to Wellington. In the evening, it takes them home again.

When I first started catching the Capital Connection in 1997, we nick-named it the Crappy Connection. It consisted of geriatric railway carriages hauled by whatever (it seemed) diesel locomotive could be spared by Tranz Rail. It was prone to delays and breakdowns, and many memorable hours were spent sitting in the carriages wondering how late we would be today. There were several diesel locomotive breakdowns (were we too heavy?) and at least one memorable occasion where the loco ran out of puff part-way up the hill, and we had to reverse back to the nearest station. Not an enjoyable experience on a busy commuter line where we believed the signalling system was in desperate need of maintenance.

But railways staff are resourceful. The guards whom we came to know by being regulars tried to keep us informed, and the diesel loco drivers reacted quickly as well. I well-remember one incident which resulted in our limping into Paekakariki Station on the northward trip home with a loco that had “burst its boiler” (so to speak) climbing up the Pukerua Bay Hill. Miraculously, within just over an hour, a replacement locomotive was scrambled and shot past us on the southbound track at Paekak. Station. In no time, it had been coupled up to the front of the train and off we went again to cheers and claps from the passengers.

On more than one occasion, the powerful electric commuter units have shunted the Capital Connection (minus diesel loco, of course) to a nearby haven. The Ganz Mavag electric units, purchased back in the 1980s (from memory) must’ve been one of the best investments NZ Railways ever made. Initially they were rather unpopular as they had the habit of steaming passengers with overzealous heating systems designed for the cold of a Hungarian winter. Now showing signs of age, they have undergone several interior refurbishments and are currently suffering an identity crisis as they prepare to be rebadged (yet again) in a new episode of our rather bumpy railway history. Despite this, their hearts are in the right place, and the powerful electric motors handle our steep Wellington terrain very well.

But back to the Capital Connection. Despite the breakdowns, the provision of a basic bar service and the virtually non-stop service to Paraparaumu resulted in patronage increasing. In November 1999, refurbished British Rail carriages were used to replace the old rolling stock, which continued running on other long-distance services. Boasting electric doors, air-conditioning, easy-access dunnies and an improved bar with free coffee, the Capital Connection really took off. The loco problems continued, but at least we had the comfort of a drink, easy-access dunnies and the lights stayed on more reliably. (Those tunnels are VERY dark when they forget to turn even the emergency lighting on!)

Over time, passenger loyalty has continued and the service reliability has improved. Not surprisingly passengers get to know each other quite well on such a long trip, and friends regularly sit together, and social events are held both on and off the train.

As I live nearer to Wellington, I no longer catch the Capital Connection but see it whizz past regularly. The British Rail carriages still look odd perched on their bogies which allow them to run on our ridiculous three foot six narrow gauge railway. But it has proven that railways that receive good patronage can attract investment. And soon, the other long-distance commuter service, the Wairarapa train, will receive a long-overdue upgrade.

Every so often as the Capital Connection zooms through the local station with its unique sound, I am reminded of one particular evening back in the late 90s. We were sitting on board it waiting for the shriek of the guard’s whistle when one of our regular fellow-passengers bustled aboard at the last minute. Under one arm he had a computer VDU and a beige computer box under the other. Puffing and panting he managed to navigate the aisle to his usual seat with his friends and unburden himself as the train jerked into motion.

One of his mates looked up from the Evening Post. “Ah, the departmental laptop!” he quipped. “You’re on call-out?” and he returned to his newspaper as we all roared with laughter.

Earthquake Swarm near Seddon Abates

Thursday, November 24th, 2005

The Swarm of shallow earthquakes occurring 10 km East of Seddon in Marlborough seems to have run its course. The swarm of 9 earthquakes, all 5 km deep, commenced on November 1st and the last event was reported by the Geonet site on November 11th. The earthquakes ranged between magnitude 3.2 and 4.8, with the largest two events (magnitudes 4.6 and 4.8) shaking goods off shelves in Blenheim.

The swarm occurred amidst a cluster of deeper earthquakes in the Picton, Blenheim and Seddon area that commenced on October 18th, bringing the total number of earthquakes reported in the area by Geonet to 17. Fifteen of the earthquakes were within a 20 km radius of Seddon, with only the October 18th event near Picton and the November 20th event which was offshore from Blenheim being further away.

A similar cluster of 10 earthquakes occurred in this area between May 25th and July 31st of 2003, but it lacked the tight swarm component that characterised this year’s sequence. The 2003 earthquakes ranged between magnitude 2.7 and 5.0 (4 were magnitude 4.1 or greater) and were located between 5 and 25 km deep. The epicentres on that occasion were all within 40 km of Seddon.

Gisborne Motorist Fined for exceeding 10 mph

Tuesday, November 22nd, 2005

Philip Thornton Kenway had the honour of being the first Gisborne motorist fined for speeding when he managed to exceed 10 miles per hour. Kenway, a pioneer Waimata settler, was also famed for bravely undertaking the first motor car journey between Gisborne and Napier in a 6 h.p. single cylinder De Dion car in 1905. En route, he and his companion had to wade waist deep into creeks to remove boulders and navigate precipitous slopes at night-time with the aid of a feeble single headlamp. No settler living on the road leading to his home would risk riding or driving on it without ringing him up to make certain that he did not intend to be out that day with his “chuffer.”
[source: J.A. MacKay, “Historic Poverty Bay and the East Coast, N.I., N.Z.” 2nd edition, 1966]

Seismic Hazard Study Favours Transmission Gully Motorway Route

Tuesday, November 22nd, 2005

A report prepared for the Porirua City Council by the Institute of Geological & Nuclear Sciences (IGNS), and published on the Council’s website, has confirmed what many of us knew – upgrading the present route of State Highway 1 between Pukerua Bay and McKay’s Crossing to four lanes would be a waste of money.

Wellington desperately needs a high quality northern motorway route that will operate in all weathers and conditions – something the coastal SH1 and Rimutaka SH2 routes cannot achieve. As recently as January 8th Wellington has been cut off from the rest of the country by storm-induced flooding and landslides on these roads.

The IGNS report confirms that the steep and unstable slopes north of Pukerua Bay township could collapse in a strong earthquake producing large landslides which might take MONTHS to clear. These landslides would be much larger than the single slide which closed the Manawatu Gorge road for several months last year.

Wellington currently faces three large earthquake threats which could trigger landslides on SH1 & 2 and other roads.

The best-quantified threat is the one-in-eight chance of a magnitude 7.5 earthquake occurring on the Wellington fault within the next 30 years. Prepared from evidence of past fault movements, this is the most quantifiable risk to the city and its suburbs.

Less well-known is the risk imposed by the movement of the South Island’s Alpine Fault. The Alpine Fault produces large earthquakes, involving horizontal movement of up to 8 metres along fault segments tens of kilometres in length. Current thinking is that such an event is overdue, as historical evidence indicates that large earthquakes occur every 100 to 300 years. The last Alpine Fault events occurred ca 1620 and 1720.

For Wellington and much of the South Island, the massive Alpine Fault is the “sleeping giant” as such a movement could occur as a series of perhaps three or four magnitude 7 earthquakes over a period of minutes, resulting in a combined energy release in excess of Richter magnitude 8.

The northern extent of the Alpine Fault passes along Wellington’s west coast offshore from Wellington, Kapiti and Horowhenua, on the western side of Kapiti Island. If this submarine section was to move in conjunction with the alpine section, there would be extensive ground shaking on the western side of the lower North Island. Any resulting tsunami would simply add insult to injury.

Sound familiar? Wellington’s last experience with a magnitude 8 plus earthquake was 150 years ago, in 1855, when the Wairarapa fault ruptured, causing 9 metres of lateral movement along a 70-odd km section of the fault.

Wellington’s third, but poorly understood threat is the possibility of a subduction thrust event on the plate boundary to the south-east of the city. It is known that the collision interface between the Pacific and Australian plates is locked under Marlborough and may have been so for millennia – hence the deformation in the upper South Island.

However, the plate interface to the north of Marlborough, where the Pacific plate is still sliding under the Australian plate has been stalled for many years – perhaps 90-100 years according to one source. If this section of plate boundary was to release the strain that has built up, then the Pacific plate would abruptly slide an unknown distance beneath the overlying Australian plate in what is known as a subduction (diving under) thrust earthquake. However, whilst there is evidence that such earthquakes do occur, seismologists are still trying to calculate how often; and face a daunting task in trying to build up a picture of past events. There are clues, but the fact that all the “fun” happens underwater, means that the picture is slow to emerge.

Clearly Transit New Zealand faces considerable challenges in addressing the poor roading infrastructure in the lower North Island and upper South Island. Like the coastal highway north of Wellington, the coastal section of State Highway 1 at Kaikoura in the South Island is a high maintenance piece of road and at risk from the same earthquake scenarios. Both these roads follow routes that were defined during nineteenth century pioneering days, when four-lane carriageways were not envisaged – the delight of having a track wide enough for a horse-drawn cart in fine weather was quite sufficient.

Even more modern roads have been found wanting in terms of design. Wellington’s urban motorway was opened in the 1970s using excavation and slope management techniques that met the standards of the time. Further additions such as the Terrace Tunnel and Ngauranga Interchange were made in later years, as funding allowed.

Following the collapse of overhead spans of expressways as a result of earthquakes in Los Angeles in 1994 and Kobe in 1995, roading authorities here acted with remarkable alacrity in strengthening the overhead section of the Wellington urban motorway at Thorndon. Some supporting columns were given kevlar jackets to reduce the impact of concrete fracture and increased footings to reduce misalignment when the soft soils liquefied. At the top of the columns, the insubstantial hips upon which the sections of roadway are hung were lengthened to try and reduce the chance of a section falling should the horizontal movement of the Wellington fault increase the distance between supports by moving them apart.

These measures, if successful, will not prevent the motorway becoming temporarily unusable following a sizeable earthquake on the Wellington fault. However, they should make it possible to quickly bridge any gaps provided a complete span does not drop.

As early as 1990, engineering and council experts were highlighting the instability of the steep slopes above the coast road north of Pukerua Bay, and their susceptibility to failure as a result of earthquakes. The main trunk railway line also traverses this unstable slope through a series of tunnels and landslide barriers. At one active section of slope, a landslide detection system controls train movement, and rail passengers who care to look can see the buildup of loose material that forms against the barriers between maintenance visits.

Attempting to expand the capacity of the Wellington coastal route along unstable narrow corridors is false economy. The land for Transmission Gully is available and progressive establishment of a road designed to modern standards and expectations should begin in earnest.

An alternative to the coastal section of State Highway 1 at Kaikoura also needs to be developed. This section of road has been closed by accidents, floods and landslides on several occasions in the past 3 years. It is a major corridor for road transport carrying freight to and from the interisland ferries.

These two sections of road are not only vital to the local communities; they are also crucial to manufacturing, tourism and service industries nationwide.

Improvements will not appear with the waving of a magic wand but, with adherence to a coherent plan and progressive funding, useful sections of improved roading can be made available in a co-ordinated fashion. A long-term vision is sorely needed.

Save It or Lose It

Monday, November 21st, 2005

I was listening to WorldFM last Saturday night, which featured a replaying of the Cape Canaveral launch commentary of the Apollo spacecraft mission in the Apollo-Soyuz joint mission back in 1975.

Back in the last days of the Cold War, this was a tremendous step forward in co-operation for the United States of America and the Union of Soviet Socialist Republics. The mission also marked the historic final launch of the Apollo Command and Service Module which had successfully ferried American astronauts to and from the moon and the Skylab space station. It wasn’t that which particularly struck me but the audio quality of the commentary and what was said.

The launch commentary had been recorded via shortwave radio by the well-known New Zealand DX-er, Chris Mackerell. Hunched over a receiver on the 15th of July in 1975, headphones on, cassette recorder at the ready, he had managed to capture the sound of something which we are all rapidly forgetting with our modern communication systems – the sound of human voice fading in and out of an eerie assortment of pops, squeaks and wails. Although shortwave radio is still widely used, it is heard less often by the ordinary public.

Nowadays we have a wide choice of television, AM and FM radio services to keep us abreast of world events. But even as recently as the early 1990s, it was necessary to resort to shortwave radio to hear unfolding events on the far side of the planet, if the few local radio stations and TV channels of the time weren’t showing interest.

The American commentator at the Apollo launch provided a fascinating mixture of his own observations and official NASA audio feeds. There even seemed to be one of those NASA squawk-boxes (familiar to us from Tom Hanks’ Apollo 13 movie) running in the background.

Notably lacking was the modern intervention of NASA’s marketing department with some trite line about “recapturing the moon” etc at the moment of the launch. Instead, we heard the countdown and the voice of one of the controllers at the Kennedy Space Centre ad-libbing as events unfolded.

It went something like this:
Controller: … the batteries are on-line…
… T minus fifty five …
… cabin is now pressurised …
… (followed by the usual last 15 second countdown)
Commentator: I can see the flame at the tail…
Controller: … it has cleared the tower …
Commentator: At one minute fifteen the flame is, oh, about 5 centimetres long [Did I mis-hear that or was he broadcasting to a French audience??? – even metricated NZ wasn’t quite using those measurements in the heat of the moment back then]
Squawk-box: peep! burble burble peep!
… peep! Roger peep!
Commentator: The escape tower has been ejected …

Real seat of the pants stuff made all the more real by the man-made and natural interference that was upsetting the signal.

Sometimes we forget that we, too, are a part of history. Whilst there is a laudable resurgence in recording the lives of our parents’ generation, we often forget to save some of the things that intrigued US during our lifetime, and in the hurly-burly of ordinary life they get pitched out when we move house. But some of this material will be of interest to our children’s generation when we have moved on.

There are several repositories in New Zealand eager to help us conserve material of historical significance. For example, the Alexander Turnbull Library will happily consider conserving photographs of notable events, interesting sequences or themes. The New Zealand Sound Archive will give help and advice on saving those snippets of recorded memories.

Save It Now – or it will be lost to later generations.

Dry Spell Broken

Monday, November 21st, 2005

The 27 day run of dry weather in Tawa, Wellington was broken when 1 mm of rain fell in blustery northerly conditions this morning.

Under Construction

Monday, November 21st, 2005

Pneumatic drills clatter, hammers go tack, tack, tack.
Electric screwdrivers whine, nail guns go crack!
This blog is under construction.
Be patient, it might take a day or two!
and then I’ll have stuff to educate and entertain you.