ABSTRACT: Local homebuyers in the Groningen earthquake regionIr. Hieke T. van der KloetHanze University of Applied Sciences GroningenResearch Centre for Built Environment NoorderRuimteh.t.van.der.kloet@pl.hanze.nl0031-50-595-2015The earthquakes after the natural gas extraction in the Groningen region of the Netherlands have a significant impact on the housing market and sustainability of the communities in this region. Since the strongest earthquake around the community of Huizinge in August 2012, with an magnitude of 3.6 on the Richter scale, it became clear there is a relation between natural gas extraction and earthquakes due to soil subsidence. As a consequence houses in the region get damaged and after research it gets obvious housing prices decline and the region will become unattractive to potential buyers of houses, damaged or not. Therefore the Dutch Petroleum Company (NAM) since April 29th 2014 offers a compensation for the loss of the housing price before and after the earthquake of Huizinge to property owners who want to sell their home. They only get the compensation after a sales deal and only if they agree with the proposed compensation. Since the compensation for the decrease in house prices has been introduced, the number of participants of the regulation is lacking behind the actual sales of houses. Our study aims to contribute to the research on the consequences of earthquakes by natural gas mining on the real estate market in the northern part of the Netherlands, especially the Groningen region. First of all we want to declare why relatively a large part of the property owners (about 60% until 2015) don’t request for the compensation regulation. Our second question concerns the buyers of the (damaged) houses in the earthquake area. Why would they buy a home in a region full of risks? Who are these buyers? We use a mixed-method approach for data collection which leads to an analysis of a unique dataset on notarial deeds of house sales in nine municipalities in the Groningen earthquake region according to The Land Registry of the Netherlands during the period 2013 until the end of 2015 as well as discovering common patterns of interview results with residents and experts. First results show that the majority of the homebuyers originate from the local earthquake area in the Province of Groningen. Reasons why property sellers after the house sale don’t opt for the compensation regulation concerns the complexity of the regulation, the used valuation model and the expected long control time afterwards.From the first results we conclude that the Groningen earthquake region still has its attractiveness for local residents and buyers. Otherwise the regulation for compensation doesn’t reach enough property sellers in the nine municipalities of the Groningen earthquake region. Advise to the Dutch government should be to generously compensate the residents of the Groningen earthquake regions for the loss of value of their dwellings, damaged or not. This will help to improve the regional development and attractiveness of areas that are effected by earthquakes.
I was somewhat surprized with the fog in Groningen upon my arrival. This is notthe fog that covers the beautiful landscapes of the northern Netherlands in theevening and in the early morning. No… It is the fog that obscures the real aspectsof the earthquake problem in the region and is crystallised in the phrase “Groningen earthquakes are different”, which I have encountered numerous times whenever I raised a question of the type “But why..?”. A sentence taken out of the quiver as the absolute technical argument which mysteriously overshadows the whole earthquake discussion.Q: Why do we not use Eurocode 8 for seismic design, instead of NPR?A: Because the Groningen earthquakes are different!Q: Why do we not monitor our structures like the rest of the world does?A: Because the Groningen earthquakes are different!Q: Why does NPR, the Dutch seismic guidelines, dictate some unusual rules?A: Because the Groningen earthquakes are different!Q: Why are the hazard levels incredibly high, even higher than most Europeanseismic countries?A: Because the Groningen earthquakes are different!and so it keeps going…This statement is very common, but on the contrary, I have not seen a single piece of research that proves it or even discusses it. In essence, it would be a difficult task to prove that the Groningen earthquakes are different. In any case it barricades a healthy technical discussion because most of the times the arguments converge to one single statement, independent of the content of the discussion. This is the reason why our first research activities were dedicated to study if the Groningen earthquakes are really different. Up until today, we have not found any major differences between the Groningen induced seismicity events and natural seismic events with similar conditions (magnitude, distance, depth, soil etc…) that would affect the structures significantly in a different way.Since my arrival in Groningen, I have been amazed to learn how differently theearthquake issue has been treated in this part of the world. There will always bedifferences among different cultures, that is understandable. I have been exposed to several earthquake engineers from different countries, and I can expect a natural variation in opinions, approaches and definitions. But the feeling in Groningen is different. I soon realized that, due to several factors, a parallel path, which I call “an augmented reality” below, was created. What I mean by an augmented reality is a view of the real-world, whose elements are augmented and modified. In our example, I refer to the engineering concepts used for solving the earthquake problem, but in an augmented and modified way. This augmented reality is covered in the fog I described above. The whole thing is made so complicated that one is often tempted to rewind the tape to the hot August days of 2012, right after the Huizinge Earthquake, and replay it to today but this time by making the correct steps. We would wake up to a different Groningen today. I was instructed to keep the text as well as the inauguration speech as simple aspossible, and preferably, as non-technical as it goes. I thus listed the most common myths and fallacies I have faced since I arrived in Groningen. In this book and in the presentation, I may seem to take a critical view. This is because I try to tell a different part of the story, without repeating things that have already been said several times before. I think this is the very reason why my research group would like to make an effort in helping to solve the problem by providing different views. This book is one of such efforts.The quote given at the beginning of this book reads “How quick are we to learn: that is, to imitate what others have done or thought before. And how slow are we to understand: that is, to see the deeper connections.” is from Frits Zernike, the Nobel winning professor from the University of Groningen, who gave his name to the campus I work at. Applying this quotation to our problem would mean that we should learn from the seismic countries by imitating them, by using the existing state-of-the-art earthquake engineering knowledge, and by forgetting the dogma of “the Groningen earthquakes are different” at least for a while. We should then pass to the next level of looking deeperinto the Groningen earthquake problem for a better understanding, and alsodiscover the potential differences.
DBELA is a Displacement-Based Earthquake Loss Assessment methodology for urban areas which relates the displacement capacity of the building stock to the displacement demand from earthquake scenarios. The building stock is modeled as a random population of building classes with varying geometrical and material properties. The period of vibration of each building in the random population is calculated using a simplified equation based on the height of the building and building type, whilst the displacement capacity at different limit states is predicted using simple equations which are a function of the randomly simulated geometrical and material properties. The displacement capacity of each building is then compared to the displacement demand obtained, from an over-damped displacement spectrum, using its period of vibration; the proportion of buildings which exceed each damage state can thus be estimated. DBELA has been calibrated to the Turkish building stock following the collection of a large database of structural characteristics of buildings from the northern Marmara region. The probabilistic distributions for each of the structural characteristics (e.g. story height, steel properties etc.) have been defined using the aforementioned database. The methodology has then been applied to predict preliminary damage distributions and social losses for the Istanbul Metropolitan Municipality for a Mw 7.5 scenario earthquake.
MULTIFILE
In the past, textile material was used to add value to buildings in various applications, as well as improving building performance in terms or in terms of building and acoustics properties, and increasing the esthetic value.Textiles are light in weight, easy to shape, strong, insulating, moisture-regulating and can be provided with extra functions. Particularly in areas with an earthquake risk, as well as cases with a temporary demand for flexible shelters, textiles and primary use.
The pipelines are buried structures. They move together with the soil during a seismic event. They are affected from ground motions. The project aims to find out the possible effects of Groningen earthquakes on pipelines of Loppersum and Slochteren.This project is devised for conducting an initial probe on the available data to see the possible actions that can be taken, initially on these two pilot villages, Loppersum and Slochteren, for detecting the potential relationship between the past damages and the seismic activity.Lifeline infrastructure, such as water mains and sewerage systems, covering our urbanised areas like a network, are most of the times, sensitive to seismic actions. This sensitivity can be in the form of extended damage during seismic events, or other collateral damages, such as what happened in Christchurch Earthquakes in 2011 in New Zealand when the sewerage system of the city was filled in with tonnes of sand due to liquefaction.Regular damage detection is one of key solutions for operational purposes. The earthquake mitigation, however, needs large scale risk studies with expected spatial distribution of damages for varying seismic hazard levels.
The project virtually breaks down a large timber structure into pieces and simultaneously simulates and tests each piece in a different laboratory or facility. In this way, unique aspects of each facility can be used at the same time. The experiments take place in a synchronized way, which is a difficult task considering 4 countries (UK, Canada, Greece and the Netherlands) will work at the same time for testing one hypothetical timber structure. Geographically distributed hybrid testing blue sky research, timber structure testing including soil-structure-interactionHYSTERESIS project aims to use geographically distributed hybrid testing for providing experimental evidence for energy dissipation and SSI response of buildings composed of mass timber and CLT panels. The project outcomes will give a boost to the efforts of building multi-story timber structures in areas with wind and/or earthquake loading conditions. The particularities of the problem in hand and the need for testing in large scale while taking into account the SSI, dictate using a novel hybrid testing approach.
