Why Study Historical Earthquakes In New Zealand?

I've had to think hard on how to put this together. I really want to share what I do with everyone, but experiences in the past (when I did my fiction writing a decade or so back) make me incredibly hesitant to reveal too much information. Hopefully I can find a balance here; please let me know if there isn't enough information in this in order for you, the reader, to actually understand what I am talking about!

Searching the Archives

In my previous blog post I left off having decided to start looking at historical earthquakes in New Zealand for a prospective, albeit never begun, Masters project at Plymouth University. About a month later (early April 2018) I began to search the internet to see what I could find. The first, and most obvious port of call, was the GeoNet website. On the website you can find all sorts of information about earthquakes: live seismograms, recent earthquakes, slow slip events and much more. The two pages of most use to me however are the historical events, which shows a variety of significant earthquakes which have struck New Zealand between 1848-present, and the earthquake search which enables you to search for earthquakes within the GeoNet database. I'll get back to database later in this blog post.

Both of these pages are very powerful. The historical events summarises all sorts of quakes, from significant 19th century quakes (1848 Marlborough, 1855 Wairarapa, 1868 Cape Farewell & 1888 North Canterbury) to more moderate 20th century events (1966 Seddon, 1976 Waikato & 1990 Lake Tennyson). New Zealand's more recent seismicity has a far greater share of the list's contents, because a) recent seismicity has been the most active to strike New Zealand in 80-90 years and b) most people are going to interested in reading about the more recent significant earthquakes than those in distant living memory or beyond living memory.

Isoseismal Map of the 1868 Cape Farewell Earthquake (Downes & Dowrick, 1995)

And herein lies the problem for New Zealand's historical catalogues. There are three main sources available for historical quakes in Aotaeroa: the GeoNet earthquake database (also known as the National Earthquake Information Database, or NEID for short); the two editions of Gaye Downes & David Dowrick's Atlas of Isoseimal Maps of New Zealand Earthquakes (published 1995 & 2014); & George Eiby's An Annotated List of New Zealand Earthquakes (published 1968). The latter author also has a couple of papers documenting earthquakes which occurred in the early years of New Zealand's historical after the Pākehā arrived in the early 20th century, whilst there are a myriad of papers documenting individual historical earthquakes from different disciplinary perspectives (seismology, tectonics, ground motion, engineering geology, etc.)

This is a fantastic start and in fact the available sources mean that historical earthquakes post-WW2 are fairly well documented, with all earthquakes above magnitude 6.0 known, and many more moderate (magnitude 4.5-6.0) earthquakes also documented. Many of these events are not included in GeoNet's historical events page (e.g. 1948 Mw 6.4 Waiau, 1962 Mw 5.9 Westport, 1974 ML 4.9 Dunedin & 1993 Mw 6.2 Ormond), but can be found in the NEID.

Isoseismal Map of the 1974 Dunedin Earthquake (Downes & Dowrick, 2014)

However, for the region targeted for the prospective Masters project back in 2018, there had been no significant quakes since a Mw 5.9 in 1951 damaged a township familiar with seismicity in the 20th century. This meant that, with a fairly complete catalogue after 1951, to find other earthquakes which may have adjusted the stress in the region I had to look earlier. This meant investigating earthquakes which may not be in the small collection of databases and catalogues available.

Another important discovery from the above sources was found in Downes & Dowrick (2014). In the preface to the Second Edition, the final paragraph notes that "there are many deep and some shallow earthquake with magnitude M≥6 for which there are insufficient data for an isoseismal map", as well as "large earthquakes in remote locations... or locations that were sparsely populated may not have bene recognised yet, as in-depth research on parts of the historical record, principally, 1855-1900, is incomplete." Both the need to look for specific regional quakes prior to 1951, and this paragraph, was encouragement to see just what could be found. Now it was just to find sources of information to do this.

By luck I happened upon a website which may be able to help and I have continued to use ever since. This is Papers Past, a New Zealand government website containing thousands of different digitised newspapers, magazines, journals, letters, diaries and parliamentary papers from the 19th, 20th & early 21st centuries. A treasure trove for researchers into New Zealand's post-colonisation history, it also contains plenty of references to earthquakes. One journal in particular, the Transactions and Proceeding of the Royal Society of New Zealand, contains in every edition from 1869-1902 tables of earthquakes in the respective year felt in the towns & settlements of New Zealand. These are an invaluable source for any wannabe researcher into New Zealand's historical seismicity, and they were one of the first gold mines I happened across - in fact it is the basis of much of my 19th century research.

However my main focus initially was on using the newspapers found in the online archive. Within a week of commencing my research I had got a brief overview of seismicity from the 1900s decade (1901-1910) using issues of the New Zealand Herald newspaper, based in Auckland. Further searching revealed that many quakes were missing, and with my foci changing over the weeks and months that decade still requires a lot of work.

Page 5 of the Monday, September 3 1888 issue of The Press newspaper (Christchurch), showing the some of the articles on the North Canterbury Earthquake two days prior (The Press, 1888)

For the first year and a half I did not have a specific aim besides trying to find as many earthquakes as possible. Due to my increasing understanding of existing knowledge of New Zealand's historical seismicity, I set an arbitrary end date of 1929 (March 1929 Arthur's Pass & June 1929 Buller Earthquakes were the two most significant earthquakes to strike New Zealand in at least a quarter of a century, and in the case of the latter since 1855). A beginning date for the catalogue I was gradually constructing was post-1855 (the Mw 8.1-8.2 Wairarapa Earthquake is the largest quake in post-colonisation New Zealand's history), and currently it is 1862 (the year of earliest quake I have in my catalogue).

By the end of last year I had decided that I must recommence on my education after a year of retail work & gradual recovery from my final year at Plymouth. I began to make enquiries, both in the UK and abroad, with a vague idea of wanting to do a Masters project on historical New Zealand seismicity. At about this time I decided to take a look into seismicity in the latter part of my catalogue's temporal range. In the process of searching I came across a few earthquakes which caught my attention. An email sent to New Zealand scientists in January of this year proved the spark to deciding on two possible Masters projects. Further enquiries ruled out one option - it would require personally looking through archives in New Zealand to find further sources of information on the earthquake, despite the apparent importance of this quake to seismic hazard in New Zealand - and added a lot of possibilities towards the other option.

At present it is still early days in putting together the Master project; for a start it is yet to be proposed, owing to the course not yet commencing. Data collection is still ongoing, although it is making good and steady progress. What feels most exciting to me is being able to share a portion of what I have found*, and perhaps hint at just how much more is yet to revealed. 

At present my All Quakes Database (which ironically excludes those already documented in Downes & Dowrick or the NEID) contains ~1550 individual earthquakes between 1862-1929. Recent data acquisitions (via GNS Science and a personal book acquisition) reveal that in reality, there most likely is a sum four or five times greater than that total to be found and documented. Many of these will most likely only have one felt location with no relevant information from which to derive an estimated intensity, but a sizeable minority will prove helpful in at bare minimum producing isoseismal maps, and at best relatively reliable estimates of location, magnitude and depth.

My desire to complete a Masters project on a small aspect of this research is twofold: to prove to myself that I can produce something worthy of being put out there into the wide scientific world, and to prove to others that what I am attempting to do is worthwhile. A catalogue of moderate and significant earthquakes is all very well and good, but it needs to be applied to things which have relevance to people today. And this is the task I have decided I wish to take on.

Final Note

I shall endeavour to share these holiday finds with you all soon. One of these was indeed an extraordinary find, owing both to it's contents and most certainly it's age. Another was written by the most popular writer on seismicity at the time of it's publication, and contains some beautiful plates. The third is a more recent publication (albeit nearly three decades older than myself) on a really significant New Zealand earthquake and was a nice find to accompany the others.

*This is a fun example of choosing the correct word. Technically speaking I am finding these quakes, but only because they have been forgotten or neglected in terms of research. A term I often unintentionally use is discover which would infer I was the first person to feel the quake, which would be impressive given I would need to be at least 70 years older than I am. Perhaps find and rediscover are the best terms to use, as I am both finding references to them, and in doing so rediscovering earthquakes felt by New Zealanders 90 or more years ago.

Literature References

Downes, G.L., Dowrick, D.J. 1995. Atlas of Isoseismal Maps of New Zealand Earthquakes. Institute of Geological & Nuclear Sciences monograph 11. Lower Hutt: Institute of Geological & Nuclear Sciences.

Downes, G.L., Dowrick, D.J. 2014. Atlas of Isoseismal Maps of New Zealand Earthquakes - 1843-2003. Second edition (revised). Institute of Geological & Nuclear Sciences monograph 25. Lower Hutt: Institute of Geological & Nuclear Sciences.

Eiby, G.A. 1968. An Annotated List of New Zealand Earthquakes, 1460-1965. New Zealand Journal of Geology and Geophysics. 11:3, p. 630-647.

Eiby, G.A. 1968b. A Descriptive Catalogue of New Zealand Earthquakes, Part 1 - Shocks Felt before the end of 1845. New Zealand Journal of Geology and Geophysics. 11:1, p. 16-40.

Eiby, G.A. 1973. A Descriptive Catalogue of New Zealand Earthquakes, Part 2 - Shocks Felt from 1846 to 1854. New Zealand Journal of Geology and Geophysics. 16:4, p. 857-907.

Picture References

Downes, G.L., Dowrick, D.J. 1995. Atlas of Isoseismal Maps of New Zealand Earthquakes. Institute of Geological & Nuclear Sciences monograph 11. p. 29. Lower Hutt: Institute of Geological & Nuclear Sciences.

Downes, G.L., Dowrick, D.J. 2014. Atlas of Isoseismal Maps of New Zealand Earthquakes - 1843-2003. Second edition (revised). Institute of Geological & Nuclear Sciences monograph 25. p. 604. Lower Hutt: Institute of Geological & Nuclear Sciences.

The Press (Christchurch, New Zealand), 1888. "Earthquake", 3 September 1888, p. 5. Accessed via: https://paperspast.natlib.govt.nz/newspapers/press/1888/09/03/5, National Library of New Zealand.

A Little About Me

I'm back from holiday and...

As my second blog post as I rejuvenate this blog, I thought I would write out a post explaining how I have got to point where I have decided to focus on historical seismology. As one prominent current historical seismologist has stated a few times, those who study the subject are a rare breed. How one gets interested in this topic then is perhaps something of interest to you.

A Quick History of My Interest in Seismology

As I stated in my last blog post I visited New Zealand's South Island in February 2010 with my grandfather and parents. I was in my mid-teens, quite impressionable, and I felt I knew what I wanted to do in the future (an author of fantasy fiction, having already gone through dreams of wanting to be an ancient historian & architect - all of these represent key interests of mine today). I had never been on a long-haul flight before (my only previous flight having been in autumn 2009 from Southampton Airport to Dublin, a journey not much more than an hour in length, as opposed to the 9 hour flight to Singapore, the 8 hours to Sydney, and the 2 hour or so to Christchurch). This was an adventure I was unlikely to match in a long time, if ever.

Both my grandfather and my father are avid motorcyclists, and my Granddad had been to New Zealand on two or three occasions in the previous 14 years. During his three visits - all for biker international rallies - he had befriended two different biker couples who lived in Christchurch. In February 2010 there was an International Rally for BSA bikes in Christchurch, and as my Granddad was nearly 80 this was likely to be his last chance to visit them. We arranged to go with him, and despite a very cold January feeling like it was threatening being able to fly away the weather relented by the time we left in early February.

Winter 2009-2010 was a tad bit cold in the UK. Exact date unknown

The first week was spent in Christchurch and involved several runs out to various sights. The first ride out was to Cust, a small village on the road between Woodend and Oxford in the Canterbury Plains. The second involved a ride across the Port Hills, round the north-west side of Lyttelton Harbour, and down to Wigram Airfield & Air Museum. The third day was a free day to do what you wished with, and we went into central Christchurch and saw the Cathedral Square, as well as a small bike museum hidden away in a small brick building, before going through the Lyttelton Tunnel and looking around Lyttelton itself. We saw the Timebell Station from the road (at the time it was having necessary renovations made to it, so sadly we could not take a look around).

Our fourth day took us down to Akaroa Harbour and a nice boat trip around it. The fifth took us to Godley House in Diamond Harbour, on the south side of Lyttelton Harbour. On the return trip I took my favourite picture from the entire holiday - the view of Lyttelton Harbour from the Summit Road looking east, from some point above Governors Bay. This was effectively the final day of the International Rally.

Godley House, 12th February 2010

The remainder of the holiday was spent touring around the southern half of the South Island in a rather cramped and poorly-maintained campervan. Despite the problems, we enjoyed visiting many places in South Canterbury, Otago & Southland - Oamaru, the Moeraki Boulders, Dunedin, the Otago Peninsula (to see the great albatross on a rather cloudy day), Curio Bay, the Bert Munro (The World's Fastest Indian) exhibitions in a department store in Invercargill, the Mirror Lakes and Milford Sound, Queenstown, Cromwell, Wanaka's National Transport and Toy Museum, Mount Cook & the Tasman Glacier (which we landed on), Lake Tekapo and Geraldine.

Unsurprisingly the whole holiday had a profound impact on me. What had struck me wherever we went was how welcoming, compassionate and kind New Zealanders were. That feeling stuck with me as we witnessed from afar - on the television news and in letters from our family friends - the devastating earthquakes which wracked Christchurch and it's surroundings. Places we had seen - the Anglican Cathedral, the Press Building, Lyttelton Timebell, Godley House - were ruined. All of these places, and many more besides, have subsequently been demolished or left to ruin. I witnessed from afar as the soul was ripped from the heart of Christchurch by forces of nature we were powerless to stop or combat.

The Lyttelton Timeball Station, 10th February 2010

At the time they struck I had little knowledge of earthquakes. I had seen news reports of several significant quakes over the years: I believe I can recollect Gujarat in 2001, as well seeing the news reports on Bam in 2003, Sumatra in 2004, Kashmir in 2005, Sichuan in 2008, L'Aquila in 2009 and of course Haiti in January 2010. All of these had been significant moments in my lifetime, but I had never had need to look, nor was taught about, how and why these events occurred. I had no real idea what a fault was, although I had some knowledge about tectonic plates and many previous earthquakes (having an adult Atlas is an invaluable learning tool, even when you are primary school age!).

Therefore I began to actively find out what was causing these earthquakes, using the Internet as my guide. I stumbled across GeoNet at some point, and can recollect what I believe was the original layout of the website (if it was not the original, it was certainly the second iteration). I began to glean information on my own, and by the end of secondary school made the decision to find a local college where I could do a qualification in Geology. I had decided that if I could do anything in the future to help mitigate future earthquakes like Christchurch, I would feel I had done something worthwhile. I had also been encouraged by one of my grandfather's friends in Christchurch to try and do my university degree in New Zealand - something I have not done yet, and perhaps will be able to satisfy her wishes at a later date.

Towards the end of my first year at college a qualification opportunity arose in which one could complete a piece of research on a topic of their choice (it was encouraged that the topic of this Extended Project related to one of the other courses you were studying, though it was not limited to this). I decided I had to do one on New Zealand earthquakes. For several months I had few ideas what exactly to do the project on, until on the morning of the 19th July 2013 a moderate magnitude earthquake struck in the Cook Strait between Wellington and a small Marlborough town called Seddon. The sequence intensified over the next two days, and by the middle of August there had been two mid-M6 strike-slip earthquakes which had caused significant damage in the Seddon and Ward townships and minor damage in Wellington. My topic was found, and by hand-in date in November 2013 I had a document which I was proud of. I got top grades, which greatly pleased me, and I went off to university at Plymouth with high hopes for the years to come.

Fault Map of the Cook Strait Sequence showing the different faults involved (Gurney 2013, unpublished)

Personally, those hopes were somewhat dashed, though through no fault of the department or staff. As many undergraduates find, living away from home is a tough ask, and perhaps my failure to socialise well led to the problems later on in my degree which resulted in my two-year hiatus from education. Whilst my education continued, I kept up with my own personal research. I began my original blog (United Kingdom Earthquake Bulletin) at the start of my Bachelors degree in September 2014, and set up a Twitter account alongside it. Most of you who are reading this will be doing so purely because I started this endeavour 6 years ago. Perhaps this Twitter account has been the most influential part of my development - I have encountered many brilliant and kind people who have helped me learn so much about my passion.

My research into Cook Strait had led me to encounter the concept of stress triggering, particularly relating to the Landers & Big Bear Earthquakes in 1992, and the North Anatolian Fault's unzipping between 1939 and 1999. This seemed to be a way in which future earthquakes could be forecast, if not predicted, and indeed it is still used as a crucial tool in understanding seismic hazard for the near future. Unfortunately I always felt I lacked the skills in mathematics and physics to pursue this (at secondary school I had been fantastic at these subjects; at college I suddenly & inexplicably struggled), and it was never taught during my Bachelors. Nonetheless the idea intrigued me, and I floated the idea of using the method on the November 2016 Kaikoura Earthquake to a couple of lecturers at UK institutions when looking for a Masters in late 2016 and early 2017.

As luck (or perhaps lack of luck) would have it, as I laboured to complete a now deferred dissertation in an unplanned fourth year, a lecturer (Dr Zoë Mildon) began at Plymouth who specialises in stress triggering. By the time she started I had been forced to leave my lodgings in Plymouth (twice, but I digress & do not wish to discuss this subject in a blog), so I managed to have a meeting with her in late February. Despite my misgivings, the fact she had begun at Plymouth made me seriously consider staying on to do a Masters in Geology (which would have been a fifth year at Plymouth). 

During the meeting, we forged an idea inspired by Zoë's work on the historical earthquakes in the Apennines and how stress triggering explained why the earthquakes over the past few centuries had occurred in the order and places they had. Once back home I began to look into how I may be able to find information on historical earthquakes which had occurred in the area of interest in New Zealand, and any which might possibly have been missed. The project never got off the ground - I decided against staying on at Plymouth for personal reasons - but the seed had been sown. Now all that was to be done was to begin the search...

[To Be Continued]

A rather snowy Plymouth & Roland Levinsky Building, 28th February 2018

P.S. I promised to tell you share some exciting things from my recent holiday. I shall do so soon, but I think I'll do this in small doses. Besides I am using my exciting things for research currently and will need to find a good way to photograph them in all their glory!

August 2020 NZ Seismicity Summary & Making A New Start

A Brief Update

It has been a good while since I did a blog post - both of my Earthquake Bulletin blogs have been severely neglected for a year or more, so I thought it might be nice to write a new one as I am beginning on a new stage of my journey.

I graduated with my Bachelors degree in Geology at the University of Plymouth about two years ago (September 2018). I had a terrible last couple of years; I ended up doing four years, one more than normal because I deferred my dissertation, only to get my additional year totally messed up by other things. As a result I have spent the last couple of years doing a job to get some money coming in, recovering my mental health and at the same time developing an idea for a Masters project, and exactly what I would like to do as my career.

I write this blog post at near enough the same time that, 10 years ago, events shook into motion which changed my life. At 4:35 am on the 4th September 2020 a Mw 7.1 earthquake struck about 40km west of Christchurch, causing significant damage to rural areas, and substantial damage to heritage & historical buildings in the Christchurch urban area. I had visited the city only 7 months prior on my "holiday of a lifetime", so this was quite personal to me, especially since family friends lived in the city's western suburbs (Ilam & Riccarton).

When the second Christchurch quake struck in February 2011, I decided that I wanted to know more about why earthquake occurred, and if there was anything that could be done to mitigate them. That began my journey into studying earthquakes, which on a professional level I have done nothing, but on an amateur level I have done plenty. I began my Twitter account about 6 years ago at the beginning of my undergraduate course, and since then have built up a substantial, and frankly a surprisingly kind & considerate, network in the seismological & hazard communities.

At last, with my mental health in a very good state, and with nearly two and a half years of part-time research behind me, I have decided to progress in my career ambitions. In a month's time I will be starting a Masters at the University of Portsmouth in Geological & Environmental Hazards. This should be a really good stepping stone towards where I want to go, and should provide plenty of expertise & assistance in my progress. I also hope it will allow me to do a research project I have been developing since the beginning of this year (more on that in the coming months I hope).

Summary of August Seismicity

Now that I have discussed where things are with me, I thought I would do a short summary of August's New Zealand seismicity. By and large, the years since the November 2016 Mw 7.8 Kaikoura Earthquake have thankfully been relatively quiet for earthquake in New Zealand. That said, there have been some decent earthquakes which have been widely felt across the country, and a couple of damaging quakes too (for example the 25th May Offshore Levin Earthquake, which caused minor chimney & masonry damage in Foxton Beach and other nearby coastal communities).

August has proven to be a relatively quiet month in keeping with post-Kaikoura seismicity, but nonetheless some widely felt quakes have occurred. The first of these, on the 8th August, was a Mw 4.2 earthquake beneath the northern South Island, which was felt from Kaikoura to Paraparaumu, and was also felt on the West Coast (Greymouth, Westport, Karamea), Tasman (Takaka, Motueka, Richmond), Nelson, Marlborough (Picton, Blenheim, Seddon) and the Wellington area. The quake was the result of reverse faulting at a depth of 76km, and was therefore associated with the subduction of the Pacific Plate beneath the northern South Island (Indo-Australian Plate). The quake struck at 8pm in the evening, so would have been more easily noticeable than it would have been during daylight hours.

The second sizeable quake, on the 12th August, was a Mw 4.9 earthquake in northern Fiordland, which was felt from Invercargill up to Greymouth. The quake was strongest in the Lake Country (Glenrochy, Queenstown, Arrowtown, Wanaka, Te Anau), and was a relatively standard Fiordland earthquake. It was the result of oblique reverse faulting at a depth of 17km, and may have been associated with the northernmost part of the Fiordland Subduction Zone. The quake struck at 10pm at night, so was more noticeable in Dunedin than would perhaps have been anticipated owing to many people being in a stationary position (sitting, laying down).

The third significant quake, on the 26th August, was a ML 3.3 earthquake beneath Christchurch. Despite it's very small magnitude, as many ~M3 quakes in Christchurch do, it packed a reasonable punch, with more than 1,000 felt reports received. The quake was felt throughout almost all of the city, and was weakly felt in Lyttelton. No moment tensor or focal mechanism is available for such a small quake, but this was one of the many aftershocks from the 2010-2012 Canterbury Earthquake sequence which is still ongoing, even if the frequency and magnitudes of the earthquakes are significantly reduced from it's peak nearly a decade ago. The quake struck at about midday, so was perhaps not as well observed by people as it would have been had it struck in the evening or during the night.

The final significant quake, on the 29th August, was a Mw 5.5 earthquake beneath the Bay of Plenty, ~120km east of the Coromandel Peninsula. This quake, though a good distance offshore, woke many people up in Tauranga, the Coromandel Peninsula, northern Hauraki & Auckland. It has since been followed by a plethora of aftershocks, at least 10 of which have been Mw 4.0 or larger. The quake was a result of strike-slip faulting at a depth of 5km, but many of the aftershock have been the result of normal faulting. These quakes are the result of extensional processes within the southernmost Havre Trough as it transitions into the Taupo Volcanic Zone through the Bay of Plenty & Rotorua-Taupo areas. This is part of a long extensional back-arc basin within the overlying Indo-Australian Plate, which runs parallel and to the west of the Tonga-Kermadec-Hikurangi Trench. Similar swarms/sequences have afflicted the Bay of Plenty in the past, for example in 1992 (Mw 6.3 north of Matata) and in 1994 (Mw 6.5 northwest of Te Kaha). Though this quake is far smaller than those of the 1990s, the sequence has the potential to rumble along for several weeks, producing mid-M4 aftershocks. The quake struck at about 4am in the morning, which meant most people were at rest at the time of the quake, and therefore even in the relatively aseismic Auckland where people tend to feel quakes every 5 years or so on average, many were awoken by the slow, swaying motion of this distant earthquake.

Overall, about 1600 earthquake were recorded during August 2020, the smallest a ML 0.2 near Ruapehu on the 15th August, the largest the Mw 5.5 Bay of Plenty quake on the 29th August. This is a fairly normal month in New Zealand's seismicity. Since the month ended there has been a Mw ~5.0 earthquake at about 10pm on the 3rd September beneath the northern South Island, in a similar location to the 8th August quake, which garnered more than 25,000 felt reports on the GeoNet website, from Ashburton up to Taumarunui. Shaking most likely didn't exceed MM5 - most years the highest intensity observed from New Zealand earthquakes in MM5-6 (some objects fall from shelves, perhaps some minor plaster damage or dislodged bricks from chimneys).

I will be away for the next week on a much-delayed holiday, but once back I will have a little something to share with my readers from my holiday (however many that may be of course, such a neglected blog will only attract so many readers however much I try to share it), and perhaps some seismicity news to share (hopefully not of too significant a magnitude).

Kia ora!

Jamie

Seismogram of the 3rd September ML 5.7 (Mw ~5.0) St Arnaud Earthquake from Top House broadband seismograph (NZ_THZ) - Source: GNS Science data via ObsPy

Felt reports as received by GeoNet, showing felt reports from Ashburton & Hokitika up to Taumarunui & New Plymouth - Sourced: GeoNet (GNS Science)