Criticism of Seismologists Is Nothing New

Given it has been a little while since I last wrote a blog post, I thought I'd dip my toe in the water again to see if I can get the creative juices flowing with this.

A significant part of the work I am doing currently is transcribing old felt reports and newspaper articles to do with the earthquakes I wish to base my Masters project on (proposal submission is still a long way off in April). For one of the two primary historical earthquakes I wish to focus on this means transcribing ~130 PDF pages, including newspaper articles, letters, telegrams and completed felt report forms. Currently I am ~70% complete in this task, with the other primary earthquake still to do.

One of these newspaper articles is perhaps worthy of comment. The page from which this is taken has three columns cut out of the newspaper issue and stuck onto a specific A4 form page for newspaper extracts. The first column is an opinion piece, the second and third columns report the observations of the quake from different localities. I quote the first in full:

    "Earthquakes, like big totalisator dividends, set a lot of tongues wagging, and it is to be feared that they produce a mushroom crop of prevaricators. There are those walking the streets in perfect assurance to-day who will aver that they were not in the least perturbed by last night's visitor, but the average man must admit that when he was just getting interested over the first tremor, the succeeding jolt made him think that matters were going beyond a joke. However, New Zealanders are not easily frightened by earthquakes, and it is safe to say that a great many persons commented yesterday on the "earthquaky weather" that was hanging about, and is still hanging about, for that matter. And this raises the question as to what New Zealand's official seismologist or vulcanologist was doing not to predict such an unmistakable 'quake as that which shook the city last night. The answer seems to be that he is concerned chiefly with the pie-crust of the North Island volcanic region, and if that is so nobody would be unkind enough to suggest that he should turn his attention elsewhere in the meantime."

        Star (Christchurch, New Zealand), 10th December 1925.

There are several interesting points which can be gleaned from this opinion by, one assumes, the editor of the newspaper. 

The first is how he has compared earthquakes to investments. This article in from the 1920s, when stocks and shares were all the rage in the post-WW1 world and speculative investments were everywhere. Only four years later the Wall Street Crash occurred, the harbinger of the Great Depression of the 1930s.

The second is that, despite this being simply an opinion, it actually describes the experience of the earthquake relatively well. Preliminary tremors were felt - most likely the P-waves and possibly S-waves - followed by stronger tremors (possibly S-waves and definitely surface-waves) just as people in Christchurch probably felt the earthquake was about to die down. The earthquake in question most likely had its epicentre in a region bounded by Nelson, Blenheim and Wellington (250-300km to the north/north-north-east) and fairly large by New Zealand standards (M6.5-6.7). This explains the description of it's felt effects in Christchurch, which is susceptible to strong shaking even from distant earthquakes due to it's location above unusually strong crust and thick alluvial sediments.

The third is that New Zealanders are not easily frightened by earthquakes. In 1925 New Zealand had been experiencing a relatively quiescent period in seismicity - the last deadly earthquake had occurred in 1917 at Tinui in the Wairarapa, and the country hadn't suffered a M7 onshore quake since 1904 (a deep offshore Mw 7.3 struck the Bay of Plenty in November 1914). Although moderate quakes had struck more recently in 1917 (Tinui, Mw 6.7-6.9), 1921 (Hawke's Bay, Mw 6.6-6.8) & 1922 (Motunau, Mw 6.4), none of these had been truly devastating, and much of the country hadn't experienced truly strong shaking for decades. For Christchurch the 1922 Motunau quake had caused minor damage but nothing significant, 1901 Cheviot had yielded similar results, and the last significant damage had occurred in 1888, nearly 40 years earlier. It is little wonder that the editor, and perhaps New Zealanders at large, were not concerned too much by earthquakes as an imminent danger (1929 Buller & 1931 Hawke's Bay would awaken New Zealanders to just how significant a hazard earthquakes posed in their nation).

The fourth point regards the reference to "earthquaky weather". This is a phenomenon which has been alluded to for more than a century and is nothing more than people trying to find something to explain events which they struggle to find an explanation for. Science, and in all honesty simple observations, shows that there is no one type of weather which occurs or precedes earthquakes; therefore it is impossible to say there is such a thing as "earthquake weather", because the weather which occurs at the time of earthquakes is as variable as it is when there are no earthquakes. There is also no evidence of a causal link between atmospheric conditions and earthquakes, and despite many amateur scientists from the mid-19th century (Charles Rous Marten specifically recorded the weather for 1860s earthquakes felt in Otago) to the present day none have provided irrefutable proof of any connection.

This pervading pseudoscientific belief is the basis for the editor's attacks on the scientists at the Hector Observatory in Wellington (who rather ironically preserved the article for posterity - one wonders whether their reaction was one of amusement, muted frustration or indignation). As far as I am aware none of the seismologists at the Hector Observatory (R. C. Hayes, C. E. Adams) ever issued forecasts or predictions (these being far out of the scope of the science at the time - this precedes the invention of a magnitude scale for example). Some people in New Zealand did issue predictions, but as with their successors today these were based on baseless theories utilising astronomical or astrological "methods" and were primarily to attain public fame than for any societally useful purpose.

The accusation that the Hector Observatory's scientists were focussed chiefly on the Taupo Volcanic Zone most likely stems from the most recent significant seismicity in New Zealand. During much of 1922 a significant and damaging earthquake sequence struck north of Lake Taupo, and seismologists were busying themselves investigating the cause and effects of these intriguing and unusual events during the successive years. Besides the 1922 Motunau Earthquake there had been relatively little seismicity outside of the North Island until 1925, and none of these events seem to have produced enough interest from government scientists to go in the field and investigate the source areas of the quakes. The accusation may also have some basis in the regional rivalries that had existed in New Zealand for decades (stemming from the provincial system of the 19th century), although this is more speculation than anything else.

All in all, this is a rather interesting little opinion article, and says a lot about public understanding of earthquakes, and general perception of the incipient scientific study of geohazards. It is important to understand the context of historical earthquakes not just geologically and tectonically, but also in terms of social and cultural history. This is where books such as The Great Quake Debate: The Crusader, the Skeptic, and the Rise of Modern Seismology are important and indeed necessary in the study of historical seismicity: the only way to learn about these early-instrumental and pre-instrumental earthquakes is via historical sources, and thus the data gathering process should be treated as much as a historical study as a geological one. (Whether this makes me any less of a scientist than someone who deals primarily in, for example, seismograms and what they tell us about earth processes is for you to decide).

I wish to extend thanks to GNS Science, and specifically to Paul Viskovic and the GNS Archives team, for providing me with the digitised felt reports from the early 20th century. I also acknowledge Gaye Downes & the late David Dowrick for the fantastic Atlas of Isoseismal Maps of New Zealand earthquakes - 1843-2004 which  provides the magnitudes quoted above.

A final note: it has been fantastic to see from afar the 2020 Geoscience Society of New Zealand Annual Conference in Christchurch via Twitter. I recently became a member of the society and would have dearly loved to have attended. The science being produced is absolutely incredible, and I hope I will be able to join in the research with colleagues in New Zealand in the coming years. Perhaps I'll even be lucky enough to have a poster at a future conference!